This global simulation invites you to use currently available technology to
Billions of humans living on our planet require energy for all aspects of life, and contribute to changes in global biogeochemical cycles. This simulation focuses on human-caused greenhouse gas emissions, and the expected impacts these will have on four parameters that regulate important aspects of our physical world: global greenhouse gas concentrations, ocean acidity, average global surface temperature, and sea level rise. At the top of the simulation is an interactive graph of projected greenhouse gas emissions, and effects of those emissions are shown on the impact circle below.
Can you design a future in which we have brought the projected greenhouse gas emissions down close to net zero by 2050, helping to avoid some of the worst impacts of climate change?
In this simulation, you'll be exploring ways of reducing greenhouse gas emissions.
We'll start with electricity-related emissions.
This simulation gives a semi-quantitative overview of anthropogenic greenhouse gas emissions, or human activities that release heat-absorbing (and, in the case of carbon dioxide, acidic) compounds into the atmosphere. This includes the compounds carbon dioxide, methane, nitrogen oxides, and hydrofluorocarbons. Of these, carbon dioxide is by far the most abundant (IPCC 2013). Note that this simulation excludes several other environmentally relevant compounds, such as ozone, and sulfur hexafluoride.
When predicting the impact of certain solutions on the future of global greenhouse gas emissions, unless stated otherwise, it is assumed that no technological improvements will be made. This was done to simplify the design of the simulation. As a result, predictions made within the simulation tend to be conservative.
In this model, the greenhouse gas emissions from all slider settings are added together to give the total projected global emissions in 2050, and the most recently available data is connected to 2050 with a straight line. Note that emissions are not expected to change linearly between now and 2050. The scenarios with the lowest negative impacts on human life reach peak emissions very soon, and then rapidly decrease emissions by 2050. This is simplified as the bottom line on the graph, labeled "Resilient Pathway".
The initial settings of the simulation are considered to be the outcome of continuing with 'business as usual' until 2050. The total global emissions are calibrated to match the RCP8.5 'worst case business as usual' scenario (IPCC2013) greenhouse gas emission projection in 2050. This is done so that the simulation, which is vastly simplified compared to scientific climate models, gives qualitatively meaningful predictions even though it ignores a number of important dependencies and interactions. When an input is changed, the model calculates the resulting change in projected greenhouse gas emissions, and subtracts that change from the "business as usual" starting point.
This simulation does not intend to be an all-encompassing representation of mitigation strategies, but rather an exercise in seeing how different technologies, and the various combinations of them, address the reduction of anthropogenic greenhouse gas emissions. Note that some excluded areas include waste management and plastics recycling, military aircraft carrier task forces, many emissions associated with the manufacturing of clothing and consumer goods, and building envelopes. Some of these areas are more important to the biodiversity loss issue than the climate, while others actually have low impact. Areas like food transportation and the electrical and shipping emissions from the clothing industry are included in the model, but not highlighted.
This graph shows global historical emissions data, and a range of projections for future scenarios for planet Earth. Toggle the arrows at the bottom left of the graph to see emission rates since the beginning of the industrial revolution, when atmospheric carbon dioxide concentrations were 280 ppm.(Gutschow2019)
The future projections form a triangle, which we refer to as a carbon reduction triangle. More accurately, here we have a greenhouse gas reduction triangle, since greenhouse gases, such as nitrous oxide, methane, and hydrofluorocarbons(HFCs), are included as carbon dioxide equivalents. The upper edge of this triangle is based on the RCP8.5 'worst case' or 'high emissions business as usual' scenario (Riahi 2011)(IPCC2013). This corresponds to the Shared Sociocenomic Pathway SSP5 (Riahi2017). The model is calibrated to match this projection when all inputs are at their default values. (See "General Assumptions" for details.)
The lower edge (Climate Resilient Pathway) aims for net zero carbon emissions by 2050, in line with the 2015 Paris Agreement, and the United Nations Framework Convention on Climate Change (UNFCC) recommendation to keep global average temperature increase below 1.5 degrees Celsius, in order to increase our chances of avoiding the worst impacts of climate change as outlined by the Intergovernmental Panel on Climate Change (Paris2015)(IPCC2018).
To break down this wicked problem, the triangle formed by the two extremes is divided into autofill individual wedges, each corresponding to a decrease in total greenhouse gasemissions of about autofill Gt carbon dioxide equivalents by 2050.
The concept of 'carbon stabilization wedges' was initially developed by the Carbon mitigation Initiative (CMI) and has been expanded and updated in this simulation. Historical carbon emission data were taken from the PRIMAP-hist national historical emissions time series (Gutschow2019).
The Reality Check indicator is not intended to be a quantitative measure of any sort. Rather, the Reality Check is meant to be a subjective, qualitative indicator to keep the user within the realm of possibility. What is considered possible primarily focuses on present-day technology; the feasibility of some solutions include political or socioeconomic factors.
This display shows estimated impacts of the projected greenhouse gas (GHG) emissions on Earth's climate in 2100. While we acknowledge that the local impact of particular changes will be very different in different places around the world, the green circle suggests reasonably safe global boundaries to stay within in order to maintain a habitable planet. The red circle indicates extreme levels that should be avoided. These extreme levels pose high risks, such as causing irreversible tipping points to be reached in other Earth systems.
Even a reasonably safe boundary may be problematic when the rate of change exceeds the capacity of an organism or ecosystem to adapt.
All impacts are modeled based on the total emissions to 2100, based on a linear extrapolation of the 2050 emissions to 2050. Negative emissions are not included; when the emissions pathway reaches 0, it is assumes that emissions remain at 0 until 2100.
The dashed lines represent the present-day value for each impact.
Click on each sector in the climate impact circle for details on the underlying assumptions.
Currently, global average surface temperature has increased by since the industrial revolution (IPCC 2018). Global average surface temperature change is considered to be the average change in temperature at the surface of the earth since the pre-industrial reference time period 1850-1900. Based on risk analysis by the Intergovernmental Panel on Climate Change (IPCC), the United Nations Framework Convention on Climate Change (UNFCC) recommends a reasonable boundary of , and that global temperature change not exceed in order to avoid high risks of dangerous climate effects (IPCC 2018).
Since this is an average global surface temperature, it is important to note that there are certain regions in the world that experience more extreme temperatures than others. For example, the arctic is currently warming at a rate twice the global average (NOAA ARC 2018). This model assumes that the global surface temperature will increase by 3 degrees relative to 1750 for a doubling of carbon dioxide concentration (UCAR). You can learn more about the range of temperature change anticipated for different emission scenarios in the IPCC Fifth Assessment report (IPCC 2014 SYR).
Atmospheric carbon dioxide is a major greenhouse gas (GHG). Current carbon dioxide concentration in the atmosphere is (NOAA 2019)—this means that out of every million molecules of air, of them are CO2. In 1750, prior to the industrial revolution, this value was 280 ppm (NOAA 2019). The reasonable boundary for atmospheric CO2 is (which was surpassed before 1990), and it should not go above (OECD 2012).
Adapting to a changing climate is possible for some animals and humans, but becomes more difficult the faster change occurs. Both the current amount of greenhouse gases in the atmosphere and the rate of change since the beginning of the industrial revolution are unparalleled in human existence. (AR 2017)
To estimate atmospheric CO2 in 2100 from Carbon dioxide emissions, it is assumed that every 17.3 Gt of CO2 eq raises concentrations by 1 ppmv (SSCO2). You can learn more about the range of atmospheric carbon dioxide concentrations anticipated for different emission scenarios in the IPCC Fifth Assessment report (IPCC 2014 SYR).
There are two main contributors to sea level rise: ocean expansion and melting ice. Water expands as it warms, and the melting of land-based ice (such as the glaciers of Greenland and Antarctica) adds more water to the oceans. The melting of floating ice does not contribute to sea level rise (try this with a glass of ice water!)—but has other effects, including changing Earth's ability to absorb or reflect sunlight. Sea level rise also affects coastal and island communities-the ocean rise floods habitable areas, as well as low-lying agricultural lands.
Currently, global sea levels have risen on average by (Lindsey 2018). Indicated by the green circle, a "reasonably safe" boundary for sea level rise is . Indicated by the red circle, a sea level rise above represents an extreme level (see Climate Impact Assumptions). (WEF 2019).
Sea level rise is modelled here using the following method: (NOAA SLR 2012):
E(t) = 0.0017t + bt2,
where which E(t) is the sea level rise, t is the time since 1992, and b is a constant that scales linearly with net emissions between 0.0000271 (for net 0 in 2050) and 0.000156 (current starting point). You can learn more about the range of sea level rise anticipated for different emission scenarios in the IPCC Fifth Assessment report (IPCC 2014 SYR)
When carbon dioxide reacts with water, some of it forms carbonic acid, increasing the acidity of oceans. pH is a measure of acidity: more acidic environments have a lower pH. Lower ocean pH makes it difficult for many shelled organisms to grow. Since the industrial revolution in 1750, the ocean pH has decreased by 0.1 units, from 8.2 to 8.1 (NOAA OA). Because pH is a logarithmic scale, this actually corresponds to approximately 30% increase in acidity. When ocean acidity rises, carbonate in the shells of sea creatures becomes more soluble, and their shells can begin to dissolve (NOAA OA). To prevent this, it is recommended that ocean pH remain above 7.7 and not go below 7.4 (Caldeira 2003).
The modelling of ocean acidification is fairly complicated, and depends on the salinity, and temperature of the water, as well as the concentration of carbon dioxide in the atmosphere. In this simplified estimation, carbon dioxide concentration is calculated from your emission choices in DOCs, and the remaining values come from (Bozlee 2008). To see how ocean acidification is actually modelled, go to the KCVS resource "Ocean pH Learning Tool " (Click for Link) tool
This slider is non-categorical and will appear on every page.
When it comes to food, transportation, electricity, buildings, goods, etc., and their associated emissions, the world's population is an important factor. This slider is based on three scenarios from the United Nations Department of Economic and Social Affairs (UNDESA). The estimates and projections about population from UNDESA form a set of demographic data that looks at population trends and possible outcomes at the global, regional, and national levels.
The default value in the simulation is set at the medium variant projection, which is billion people in 2050. The lower limit is set at billion in 2050 based on the low fertility scenario, and the upper limit is set at billion in 2050 based on the high fertility scenario (UNDESA 2019).
In combination with lifestyle changes since the Industrial Revolution, the increase in global population is a key pressure on our global support systems. There is inherent uncertainty in population projections, and at the global level that uncertainty is dependant on the range of realistic future trends in fertility, mortality, and international migration—in addition to environmental factors like rises in the spread of disease and natural disasters.
While the medium variant projection for the global population is considered the most likely outcome, UNDESA says that there is roughly a 27% chance that the world's population could stabilize or even decrease before 2100, depending on a number of factors (UNDESA 2019). For example, access to voluntary, high-quality family planning, as well as education can substantially reduce the amount of greenhouse gas emissions generated from increasing global population (DrawdownP 2019).
This slider is non-categorical and will appear on every page.
Carbon capture and storage (CCS) refers to a variety of technologies that capture CO2 from industrial processes, and either store or use the CO2 for other processes such as CO2-enhanced oil recovery (EOR). CCS can be used in a variety of sectors, including fossil fuel processing, electricity production, fertilizer production, and concrete manufacturing. The slider in this model only considers the impact of CCS in fossil fuel production for heating and transportation, and the use of coal and natural gas in electricity production. CCS in the agriculture is considered in the "Decrease in emissions from crop and livestock management and food waste" slider.
CCS is still a fairly new technology, but currently available technologies have already been implemented at facilities around the world (GCCSI2019). However, the number of these facilities is fairly small, so the default value of this slider is set at . When implemented, CCS can reduce the emissions of a single plant or processing facility by 90%, and it is estimated that one third of facilities can implement these technologies by 2050 (Pembina2014), for a total emissions reduction of .The simulation does not consider technologies for the direct air capture of emissions. Direct air capture, which removes carbon dioxide from ambient air (containing just 0.04% carbon dioxide), is still under development.
This slider works by changing the carbon intensity of the sliders that are affected by CCS in the electricity, transportation, and buildings sectors. The icon on the sliders indicates that they are considered to be affected by CCS. These sliders also indicate the total emissions before capture and storage in white, and actual emissions in black on their carbon intensity scales.
In 2017, the global total of electricity generated was 25,679 TWh, which is approximately (WEO 2018, BP Statistics 2019). The default values for electricity assume that global behavior continues in the direction it is headed from today to the year 2050. Since cooling is 98% electric (IEAb 2019), the emissions for cooling buildings are included here in the total electricity production. The worldwide demand for cooling buildings made up almost 10% of the total electricity used in 2018, and is expected to continue to increase (TCEP 2019).
When other electricity sources are increased, the simulation will automatically decrease coal in place of the increased alternative, since coal currently has both the highest contribution to electricity generation and the highest carbon intensity. Each slider represents the share of a particular electricity source in the overall electricity mix—this means they all must add up to 100%. Once you have removed all coal shares, you will be prompted to choose to reduce another electricity source in order to be able to increase other contributions. It's important to note that the alternative energy sources for electricity are not considered carbon neutral. The carbon intensities, listed in g CO2 eq/kWh, are indicated with the symbol on the sliders.
Note that the sources for electricity in this simulation are not the only technologies that may be available in 2050. Only currently available technology has been included in this model.
The global electricity production is predicted to be approximately in 2050. Reducing electricity production to is considered to be a reasonable lower limit (WEO 2018, BP Statistics 2019). Since the simulations models these numbers as a multiplier relative to today's electricity production, these values translate into a default electricity production of —which may be reasonably reduced to .
Solar power includes a variety of technologies that generate electricity from solar radiation (sunlight). For simplicity's sake, only solar photovoltaic (PV) systems are considered in this simulation. However, keep in mind that solar thermal, solar concentrator, and photocatalytic technologies are being developed. In 2017, global electricity generation from solar PV was over 460 TWh, making up of the electricity generation mix (WEO 2018).
The default solar PV share in 2050 is set to , and it is considered reasonable to have up to of global electricity supplied by solar PV (Bogdanov 2019).
Solar PV can be either grid connected or function as a standalone system. The electricity generated depends on the amount of sunlight reaching the panels. Since sunlight varies over time, the simulation assumes that the electricity distribution system has sufficient storage capacity to compensate for the inherent variability, though this is currently still in the early stages of deployment. Another key assumption is that solar PV, with a carbon intensity of 46 g CO2 eq/kWh, can directly substitute fossil fuels to generate electricity (NREL 2018).
Most solar panels used today are made up of mono/polycrystalline silicon PV solar cells that have cell efficiencies ranging from 15-20%. While there are other solar PV cell technologies with varying efficiencies in development, they are not considered in this simulation because they are either not commercially available or do not make a significant contribution. Other environmental impacts to consider with respect to solar PV electricity generation include land-based resources and materials availability. Land requirements were estimated based on a required area of 1kW/m2, however, this land does not have to be solely devoted to solar power generation – PV panels can be installed on existing structures to minimize the area requirement, and dual use of land for beekeeping and sheep grazing is being explored.
Wind levels are not constant over time, so the simulation assumes that the electricity distribution system has sufficient storage capacity to compensate for variability. The simulation assumes that wind power, with a carbon intensity of 11 gCO2 eq/kWh, can directly substitute electricity from fossil fuels (NREL 2018). The simulation considers both onshore and offshore wind turbines and assumes that they are located in areas with sufficient wind to be viable. The land requirements are based off 2 MW Vattenfall’s Horns Rev 1 wind turbines, which occupy approximately 3100 m2.
Both onshore and offshore wind power systems accounted for approximately 16% of renewable capacity and of the total global electricity production in 2016 (WEO 2018). The default wind power share in 2050 is set to and an increase up to is considered reasonable (WEO 2018).
Wind power installations can exist in shallow waters, and the land beneath the turbines can be utilized for other purposes as well. In terms of implementing wind power, there are other things to remember, including:
In 2017, there were 29 countries with operative nuclear plants that produced 2637 TWh, which is about of the world’s electricity (WEO 2018, Drawdown N 2019). Using nuclear technology as an electricity source tends to be complicated. On the one hand it is a technology that can help supply the world with electricity while avoiding the emissions that drive climate change, easing the energy transition substantially (WEO 2018), Drawdown N 2019). On the other hand, public acceptance can be an issue due to concerns with tritium releases, abandoned uranium mines, mine-tailings pollution, and radiative waste, among others (Drawdown N 2019). As a result of these complications, many experts predict that nuclear growth will be limited in the future, so the default nuclear power share in 2050 is set to (WEO 2018). However, an increase up to is still considered reasonable (WEC 2016).
Nuclear plants use fission of atoms. This splitting of atomic nuclei releases energy, which is used to heat water and power steam turbines to generate electricity. Current nuclear technology employs uranium fission reactors, so this simulation does not include alternative nuclear fuels such as thorium, which are still in development. This simulation assumes that nuclear power can directly substitute coal power. Nuclear electricity has a carbon intensity of 16 gCO2 eq/kWh; however, unlike other alternative electricity sources most of the emissions are from fuel processing and decommissioning stages of operation rather than manufacturing and installation (Sathaye 2011, Warner 2012).
In 2017 global electricity generation from geothermal electricity was approximately 85 TWh, making up less than of the electricity generation mix (WEO 2018). The default geothermal electricity share in 2050 is set to and an increase up to of electricity shares is considered reasonable (WEO 2018), Drawdown G 2019).
Geothermal electricity uses heat from the earth to generate power. Note that geothermal electricity that provides only heat is not considered in this section of the simulation, but rather in the buildings section. The carbon intensity of geothermal is 37 g CO2 eq/kWh and accounts for implementation of the energy resource (NREL 2018).
Different types of geothermal electricity production include steam-driven or binary cycle plants. Less than 10% of the planet contains prime geothermal conditions (Drawdown G 2019). Geothermal is reliable, abundant and efficient, in part because it can take place at all hours and under almost all weather conditions (Drawdown G 2019). Upfront costs like drilling are expensive, but the heat source itself is free (Drawdown G 2019).
Hydroelectricity (often shortened to hydro) uses flowing water to drive a turbine that can generate electricity. To keep things simple, this simulation only considers reservoir-based or run-of-river hydroelectric plants since tidal and wave-based hydroelectric power technologies are still being developed. Like the other renewable sources considered in this simulation, hydroelectricity is not carbon neutral, and has a carbon intensity of 4 g CO2 eq/kWh (IPCC Hydro 2011).
In 2017 global electricity generation from hydroelectricity was approximately 4109 TWh, making up the highest share of renewable electricity options in the overall mix at (WEO 2018). The default hydroelectricity share in 2050 is set to due to experts expecting solar and wind to dominate shares in the near future. However, an increase up to of electricity shares is considered reasonable (WEO 2018, Drawdown H 2019).
Large hydroelectric dams produce huge amounts of electricity and are reliable, but they must be installed on a suitable river and have significant impacts to keep in mind (Drawdown H 2019)(IRENA 2018). Hydroelectric dams occupy large amounts of natural and human habitat, affect water movement and quality, sediment patterns, and fish migration. (Drawdown H 2019) Smaller run-of-river technologies are placed within a free-flowing river or stream without creating a reservoir,however this introduces variability as the flow of rivers depends on seasons and weather patterns (Drawdown H 2019). While run-of-river technologies have the potential to impact the surrounding environment, careful design and installation can ensure that is ecologically sound (Drawdown H 2019).
While still significant, natural gas has lower carbon intensity relative to coal at 461 g CO2 eq/kWh (Heath 2014). This simulation assumes that natural gas can replace coal with minimal modifications to current infrastructure.
Natural gas accounted for of global electricity production in 2017 and second to coal, is one of the primary fossil fuels used in electrical power generation (WEO 2018). The default share in electricity production for natural gas in 2050 is and can reasonably be substituted by other alternative sources (WEO 2018).
All emissions from natural gas electricity are considered capturable, so the "Capture and Storage of Fossil Fuel Emissions" subtracts a percentage o the total carbon intensity of this slider.
Biomass can be harvested to generate steam for electricity production, or can be processed into oil or gas. Biomass has a carbon intensity of 47 gCO2 eq/kWh for electricity generation, however, if use and replenishment remain in balance it can be considered to produce net zero emissions (Drawdown B 2019, O'Conner 2013).
In 2016 global electricity generation from biomass electricity was approximately 500 TWh making up of the electricity generation mix (WEO 2018). The default biomass electricity share in 2050 is set to and an increase up to of electricity shares is considered reasonable (WEO 2018, Drawdown B 2019.
Biomass is an alternative energy source because it employs carbon that is already in circulation – from the atmosphere to plants and back again. Electricity from biomass is most effective in reducing emissions if appropriate feedstocks are employed, such as waste from mills and agriculture or sustainably grown perennial crops (Drawdown B 2019). Annual grain crops like corn and sorghum deplete groundwater and require high inputs of energy (Drawdown B 2019).
In 2017, coal accounted for percent of the global electricity production. Coal has a carbon intensity of 1001 g CO2 eq/kWh assuming an efficiency of for the average coal-fired power plant (Whitaker 2012). However, they could reasonably increase to efficiency (Whitaker 2012). The simulation sets the default value for coal electricity production in 2100 to .
All emissions from the production of coal electricity are considered capturable, so CCS removes a percentage of the total emissions from this source.
This page invites you to explore factors relating to the efficiency and use of cars and air travel. On this page, vehicle refers only to personal cars (or light-duty automobiles); heavy trucks, trains and boats are not considered. The emissions on this page relate only to use, they do not include the emissions associated with the rest of a vehicle or airplane's lifecycle (production and disposal).
Each person in the world rides about (ICCTTR 2017)in light-duty vehicles. Because of solutions such as public transport, more walkable cities, and bicycle infrastructure, we assume that this can be reduced by 10% to in 2050(Drawdown BI 2020) (Drawdown WC 2020),(Drawdown PT 2020).
In the Sources of Vehicle Fuel section below, the ratio of the different fuels is illustrated with a bar distribution. Gasoline-powered is assumed to be the default vehicle type; increasing other vehicle types will automatically decrease the amount of gasoline vehicles in use. If you're curious about the impact of increasing the number of gasoline vehicles, simply decrease the other options.
Carpooling is an easy way to reduce driving emissions. In this model, all people in the vehicle, including the driver, are considered occupants. Recently, ridesharing and carsharing programs have made carpooling more accessible.
Right now, average vehicle occupancy is (Drawdown CP 2020). Increasing this to is considered reasonable.
This gasoline fuel consumption slider impacts the fuel efficiency of gasoline, diesel, LPG, and biofuel vehicles, which are expected to improve at the same rate as gas powered vehicles. The unites here are in litres of gasoline equivalent (Lge) per 100 km driven. This also assumes a combination of highway and city driving. Hybrid vehicles, which generate electricity from extra energy, then use this later to power the vehicle, are included as improvement in this slider.
The average fuel consumption of gasoline vehicles is currently around (IEA TT 2020). The ICCT initiative has set a goal to decrease fuel consumption to by 2050.
There are several factors that influence the fuel consumption of vehicles.
The fuel consumption of a vehicle is not always the same! You can improve the fuel efficiency of your vehicle by:
In an electric vehicle, electricity stored in a battery is used to drive an electric motor. Note that increasing the number of electric vehicles will require more electricity production, which is accounted for here, not in the electricity sector. You will see the carbon intensity of electric vehicles change as you make changes to the electricity supply mix you select on the electricity page of this simulation.
Current sales of electric vehicles are of all light duty vehicles, which is the default number of these vehicles on the roads in 2050 (IEA TT 2020). It is projected that this can increase to (Equinor 2019). Electric vehicle technology is improving rapidly, so the consumption of an electric vehicle is very roughly approximated to be 19 kWh/100km (USDEb 2018). This does not include emissions from production of the vehicle. Look into embodied energy and lifecycle analyses for more information.
The reduction of this slider's carbon intensity comes from the reduction of the carbon intensity of the electricity mix. If the electricity mix contains coal or natural gas whose emissions are captured using CCS, these reductions will show up on the carbon intensity scale for electric vehicles.
Hydrogen fuel cells react hydrogen gas with oxygen gas under controlled conditions to generate electricity, often to power a vehicle.As a rough estimate, a hydrogen fuel cell vehicle is assumed to have a fuel consumption of about 0.9 kg of hydrogen per 100 km (USDEa 2018). Hydrogen can be produced from a number of sources, but it is assumed that hydrogen produced for vehicles will come from the electrolysis of water, due to this method's simplicity, purity, and low carbon emission (Wang 2014). In electrolysis, electricity is used to split water into hydrogen and oxygen. A typical electrolysis cell operates at a potential of around 2.0 V and produces hydrogen with an efficiency of 57 kWh per kg of hydrogen (Wang 2014). Note that hydrogen currently is commonly generated by steam-methane reforming, which produces carbon dioxide, or other carbon-byproducts.
The carbon emissions from the use of hydrogen fuel cells come from the production of hydrogen itself, which here is assumed to be electricity (Rau 2018). Thus, increasing the number of hydrogen fuel cell vehicles will require more electricity production. As with electric vehicles, the impact on emissions will be larger as you decrease the emissions of the electricity supply mix you select on the electricity page of this simulation. You will see the carbon intensity of hydrogen fuel cell vehicles change as you make changes to the electricity supply mix.
Hydrogen fuel cell vehicles are the least studied of the alternative fuel vehicles presented here, so detailed information is unavailable. As a rough estimate, a hydrogen fuel cell vehicle is assumed to have a fuel consumption of about 0.9 kg of hydrogen per 100 km (USDEa 2018). Currently, of all vehicles sold are powered by fuel cells, and this is assumed to be the default number of these vehicles on the road in 2050 (Shell 2017). It is projected that increasing this to is possible(Shell 2017).
The reduction of this slider's carbon intensity comes from the reduction of the electricity mix.If the electricity mix contains coal or natural gas whose emissions are captured using CCS, these reductions will show up on the carbon intensity scale for hydrogen fuel cell vehicles.
Natural gas is a mixture of light hydrocarbons, mostly ethane, propane and butane. It can be burned in an internal combustion engine in a manner similar to gasoline or ethanol, and is stored either as a compressed gas or as a liquid. A typical natural gas powered vehicle uses liquefied petroleum gas (LPG, or autogas), which is mostly propane, and is about 25% less fuel efficient per litre than gas-powered vehicles. LPG is assumed to be pure propane, which is converted to 1.5 kg of carbon dioxide per litre of fuel burned (USEIAStats 2019). Including production, the "well-to-wheels" carbon intensity is 2.5 kg of carbon dioxide per litre of fuel burned (USDOEc).
Because propane is burned in the vehicle, direct emissions from the vehicle are hard to capture. Therefore, the "capturable" emissions from this vehicle type are assumed to be the emissions in production of LPG. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from this fuel type.
A hybrid vehicle is a combination of an electric vehicle and a gas-powered vehicle in one system. Depending on the driving conditions and distance, the vehicle can switch between a traditional gas engine, or an electric, battery-operated engine. In this section, only plug-in hybrid electric vehicles (PHEVs) are considered, whose batteries can be charged by plugging the vehicle into a source of electricity. Other kinds of hybrid vehicles are considered improvements in fuel efficiency.
It is assumed that this type of vehicle typically operates two thirds of its time on electricity, and uses its gas engine the remaining third. The fuel consumption of each of these modes are considered the same as the fully-electric or fully-gas counterparts (USDEb 2018)(USEIAStats 2019). This does not include the energy needed to produce the vehicle. Research embodied energy and lifecycle analyses for more information.
As with hydrogen fuel cells and electric vehicles, note that increasing the number of hybrid vehicles will require more electricity production. You will see the carbon intensity of hybrid vehicles change as you make changes to the electricity supply mix you select on the electricity page of this simulation.
Plug in hybrid electric vehicles currently make up of all light duty vehicles sold, which is the default number of these vehicles on the roads in 2050(Equinor 2019). Increasing this to is projected to be reasonable (Equinor 2019).
The reduction in carbon intensity for hybrid vehicles is a percentage of the processing of the gasoline used in this vehicle, as well as any emissions captured from the electricity mix. See the assumptions for gasoline and electric vehicles for more information.
A typical diesel-fuelled vehicle is about 25% more efficient than one that is gas-powered, and one litre of diesel is converted to 2.7 kg of carbon dioxide when burned (USEIAStats 2019).Like gasoline, this fuel typically comes from petroleum. Biodiesel is also available, but is not considered here. Including emissions during mining and refining of petroleum, the carbon intensity of diesel ranges from 3.2 to 4.5 kg of carbon dioxide per litre of fuel, depending on the origin of the petroleum used in production (Woo 2017), (Masnadi 2018). This simulation uses the lower value.The energy required to produce the vehicle is not considered. Look into embodied energy and lifecycle analyses for more information.
Today, of light-duty vehicles sold are fueled by diesel, which is the default number of vehicles on the roads in 2050(Equinor 2019). Projections indicate that increasing this to is assumed to be realistic (Equinor 2019).
Because fuel is burned in the vehicle, direct emissions from the vehicle are hard to capture. Therefore, the "capturable" emissions from this vehicle type are assumed to be the emissions in production of the fuel. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from this diesel fuel.
Although the burning of plant--derivedEthanol does release carbon dioxide, it is considered carbon neutral because the carbon in ethanol came from atmospheric carbon dioxide that was recently absorbed by plants. Carbon in fossil fuels such as gasoline, diesel, and LPGs was also absorbed by plants, but this was millions of years ago, compared to the scale of several years maximum in the case of biofuels. One of the most widely used biofuels is E85, a mixture of 85% ethanol and 15% gasoline.Note the production of substantial amounts of bioethanol reduces the availability of agricultural land for food production.
Presently, of all light-duty vehicles sold run on ethanol-based fuels, which is the default number of vehicles on the roads in 2050. (Equinor 2019).Increasing this to by 2050 is projected to be possible (IEATT2020).
Because fuel is burned in the vehicle, direct emissions from the vehicle are hard to capture. Therefore, the "capturable" emissions from this vehicle type are assumed to be the emissions in production of the gasoline fraction of biofuel. See the assumptions for gasoline vehicles for more information.
Gasoline is a product of petroleum refining. Used in a combustion engine, a litre of gasoline is converted to 2.3 kg of carbon dioxide (USEIAStats 2019). Well-to-wheel emissions, which include mining and refining of petroleum, range from 2.8 to 3.9 kg of carbon dioxide per litre of gasoline, depending on the origin of the petroleum (Woo 2017, Masnadi 2018). This simulation uses the lower value of 2.8 kg CO2 eq/L. Not considered is the energy needed to produce the vehicle. Look into embodied energy and lifecycle analyses for more information.
Cars running on gasoline are currently the most common vehicle type, so that one consideration is to improve fuel efficiency. You can modify the fuel consumption of gasoline vehicles using the fuel consumption slider above. This model assumes that other technologies (such as LPG vehicles and diesel-powered vehicles) will follow the same developments, so their fuel consumption will change with gasoline fuel consumption.
Since gas-powered cars are currently the most common, increasing another vehicle type will replace gasoline vehicles in this model.
Presently, of all light-duty vehicles sold run on gasoline-based fuels, which is the default number of vehicles on the roads for 2050. (Equinor 2019). It is reasonable for other vehicle types to replace all gas vehicles, decreasing this to zero by 2050 (Equinor 2019).
Because fuel is burned in the vehicle, direct emissions from the vehicle are hard to capture. Therefore, the "capturable" emissions from this vehicle type are assumed to be the emissions in production of gasoline. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from gasoline.
Aviation refers only to passenger air travel, and does not include shipping and transport. This model assumes that in 2050, 45% of people in the world will take at least one flight(Nergoni2016).
Why is aviation often targeted as a personal impact? This model assumes 45% of the global population travels by aircraft at least once per year. For those of us who do actually fly, for business or pleasure, this emission source may constitute a large part of our personal carbon footprint, or our emission contributions. Because taxi/take-off are the most emission-intensive, short-haul flights come with a larger relative emission contribution. There are currently no renewable alternatives that could be implemented at the necessary scale.
Assuming that 45% of people are taking at least one flight in a year,the average person travels , based on 2019 population and flight statistics(IATA 2019) (UNDESA2017) . Alternatives to flying, such as high speed rail and videoconferencing, make it feasible to decrease individual air travel by 30% to per person a year . it is important to note that total aviation kilometers can be reduces if more individuals choose not to fly at all.
Currently, the IATA's industry average fuel consumption is per passenger. (Rutherfordd 2018). This makes assumptions about the occupancy of the aircraft, with consumption increasing as more seats are left empty; As well, the most fuel intensive parts of a flight are the takeoff and landing, shorter flights have higher fuel consumption. Lifecycle emissions for aviation fuel or aircraft are not included here. Note that some airlines do use biofuels in an effort to reduce carbon emissions, though there is not yet sufficient research to indicate this is a feasible method for emissions reduction.
It is projected that fuel efficiency of planes could feasibly be decreased to
Land Use, Forestry and Agriculture are estimated to have contributed 23% to global anthropogenic greenhouse gas emissions from 2007-2016 (IPCC2019) - in other words, this sector contributed a quarter of our emissions in that timespan. This model includes considerations about forest use, conservation tillage of fields, and an umbrella category of total emissions from agriculture.
To reduce emissions, agricultural practices are moving toward regenerative practices, which include soil-carbon sequestration through pasture and grasslands management, perennial cropping approaches with reduced fertilization, and addition of biochar to soils. With good grazing practices, such as multi-paddock adaptive grazing, grasslands have the potential to make meaningful contributions to soil carbon sequestration.
It is important to recognize the complexity of our food system. The details of our practices must be considered in evaluating the impacts of land use, forestry, and agriculture both on greenhouse gas emissions and ecology and biodiversity (IPBES2019).
A forest, in this case, is defined to include naturally grown forests as well as replanted forests and tree plantations (FAOstat 2018). In this case, forest protection includes decreasing the threat of deforestation. Deforestation is defined as the loss of forest area, and includes both natural and human-caused forest loss. Minimizing deforestation involves anti-logging policies, increasing public awareness through eco-certifications, and forest maintenance payments (DrawdownFP 2020).
Currently, there are 4 billion hectares of forests in the world, 93% of which is natural (FAO 2019). The world's forests have an average carbon density of about (FAO 2005); it is assumed that all of this carbon is released upon deforestation. Carbon released from other sources such as soils is assumed to be negligible.
The deforestation rate for 2050 is projected to be thousand km2/year, which is a increase in forest protection from today's rate (CGDEV 2015). Because of increased forest protection and restoration efforts, it is assumed that the NET deforestation rate can be decreased to protection and restoration efforts, it is assumed that the NET deforestation rate can be decreased to km2/year in 2050 and forest protection can be increased to (DrawdownFP 2020, (DrawdownFT 2020), DrawdownTFR 2020). This means that deforestation and reforestation rates are equal; keep in mind that this still has impacts on biodiversity, carbon stored, and other ecosystem functions (FAO 0def).
Reforestation is the planting of forests in areas that historically had them, but presently do not, mainly due to deforestation. Research suggests that reforestation is a viable method for climate change mitigation because of its usefulness in carbon sequestration (Crowther 2017, Cunningham 2015).
The current reforestation rate is estimated to be thousand km2/year (FAD 2011). Because of previous record high rates and research suggesting that reforestation will greatly increase in the coming years, it is assumed that the reforestation rate can be increased to thousand km2/year (Bastin 2019). Tropical forests, which have lost 7% of their global land cover from degradation and deforestation, have a notable potential for reforestaton (Drawdown TFR 2020).
Peatland is a type of wetland making up 3% of the world's land area. It is comprised of decaying vegetation that plays an important role in sequestration. In terms of land-based carbon storage, peatland ranks the highest with the capacity to reduce (DrawdownPPR2020). Although peatland remains largely undamaged, this strong sequestration characteristic makes peatland a priority for preservation in order to minimize greenhouse gas emissions and avoid the thousands of years it takes to regrow peat.
Currently, peatland is being protected at , which is assumed to be the case for 2050, and may be reasonably increased to through re-established land management considerations (DrawdownPPR2020).
Peatland that has been damaged can be restored through rewetting. The restoration of peatland is important in avoiding greenhouse gas emissions as it reintroduces the huge potential for the land's carbon stock. Rewetting peatland has the capacity to reduce (DrawdownPPR2020).
Currently, no efforts are being adopted to restore peatland, which is assumed to be the case for 2050. Based on scenarios that include national commitments toward peatland restoration, the restoration rate may be reasonably increased to (DrawdownPPR2020).
Conservation tillage is defined as any method of soil tillage that leaves at least 30% of the soil surface covered in plant material (Busari 2015). Conservation tillage is often used to improve soil quality and minimize erosion, but another benefit is that conservation tillage allows soil to absorb carbon dioxide from the atmosphere at a rate of (DrawdownCA 2020). Soil undergoing conventional tillage practices, by comparison, cannot absorb carbon in this way (Busari 2015).
The total amount of arable cropland is currently around . Of this, of the land available for conservation tillage is expected to be undergoing this solution in 2050, where can reasonably use conservation tillage practices (DrawdownCA 2020).
The main agricultural greenhouse gas emissions are nitrous oxide (N2O), which is produced from synthetic crop and organic soil cultivation (FAOstat 2018).
There are a variety of methods that can be used to reduce the amounts of these gases that are produced (EPA 2019). Nitrous oxide emissions can be reduced through more efficient fertilization methods, and methane emissions can be reduced through methods such as more efficient manure management, alternative livestock arrangements, and changes in feed (EPA 2019, Legesse 2015).
Food waste can be decreased by improving food storage and transport, as well as awareness and behavior at the retail and consumer levels (DrawdownFW 2020). Behavioural changes when it comes to food consumption can also have a huge impact on reducing agricultural emissions. Plant-rich diets becoming more accessible, combined with the increased adoption of consuming a healthy average of kilocalories per day and less meat-based products, has a strong potential in minimizing land use emissions (DrawdownPRD 2020).
These techniques are difficult to quantify on a global scale, so the simulation allows the reduction of the overall percentage of emissions associated with agriculture. Current agricultural emissions are considered to be 10.72 GtCO2 eq (FAOstat 2018, FAO 2011). It is assumed that reducing these emissions by is reasonable—around half from a general decrease of agricultural emissions that come from things like crop and livestock production and management, and the remaining reductions from adopting plant-rich diets (DrawdownPRD 2020).
The building sector accounts for about 40% of totalCO2 eq emissions (IEAa 2019), making it an important target for mitigation. Mitigation strategies revolve around reducing emissions during building construction and operation, which include energy efficiency measures such as the transition from incandescent lightbulbs to LEDs, and improving insulation and air-tightness, as well as renewable energy measures such as using energy sources with low or no greenhouse gas emissions for heating and cooling in buildings.
In this simulation, buildings are defined as commercial and residential structures. Cooling is currently 98% electric (IEAb 2019), so that the emissions associated with cooling are already included in this simulation as total global electricity use, and electricity sources, as well as refrigerant management under the materials page. District heating is an important development in building efficiency improvements that will be integrated in this simulation in the future.
The construction and use of buildings represent a significant portion of global carbon emissions (GABC 2016). The total floor area of buildings worldwide can be projected to reach 402.5 billion m2 by 2050 (GSR 2017). Since the simulation represents these values in total floor area of buildings per person, the default value is , which can be reasonably reduced to .
Embodied emissions are the total carbon emitted during the retrieval, processing, and construction of building materials. We estimate a global average of is emitted during the construction phase of a building in 2050, which will be nearly proportional to operational emissions (Arch 2019, Huang 2017). Reducing this value to is assumed to be realistic based on net-zero building solutions and feasible efforts to fully decarbonise a building's operational and embodied emissions (DrawdownB 2020, WorldGBC 2019).
The average lifetime of a building impacts the rate at which new buildings must be built. Assuming building renewal phases and architecture advancement, the average building lifetime is estimated to be about (Daigo 2017). Increasing this timespan to is assumed to be realistic.
Since most of the carbon emitted from light sources is caused by electricity consumed during use (USEERE), carbon emitted during manufacturing and disposal is assumed to be negligible. Because of this, the main factor affecting carbon emissions is the energy usage of electic lighting sources. Electric lighting sources are assumed to be 100 W incandescent light bulbs by default—low energy light sources include 10 W light emitting diodes (LEDs) or compact fluorescent lights (CFL).
Low energy light sources, such as LEDs, currently make up around of lighting in buildings, and this value is increasing rapidly. The projected default is set to , and it is assumed that having nearly all light sources use low energy lighting devices by 2050 is realistic. Note that increasing the amount of low energy lightbulbs is less effective if the current electricity supply is generated from mostly low carbon sources.
Water waste accounts for the emissions that come out of unnecessary water heating. Low-flow water taps and showerheads decrease water waste, making them a viable strategy in emissions mitigation. In this case, it is assumed that more low-flow water fixtures leads to less water waste, which in turn leads to less emissions in water heating.
For each additional percentage share of low-flow water fixtures, it is estimated that is saved (Drawdown WS 2020). The projected default share of of low-flow water fixtures is set to —increasing this to is considered to be reasonable.
Currently, around half of the world's population use traditional cooking stoves that rely on solid fuel combustion. These stoves also lack proper ventilation, which combined with inefficient fuel combustion, increases greenhouse gas emissions and air pollution within the house. In this case, an increase in clean cookstoves would mean implementing proper ventilation and efficient fuel combustionin in stoves (Drawdown ICC 2020).
For each additional percentage of clean cookstove adoption, it is estimated that is saved. The projected adoption of clean cookstoves in 2050 is assumed to be the same as today's——increasing this to is considered to be reasonable as efforts toward total access to clean cookstoves increase while still being limited by cost considerations (Drawdown ICC 2020).
Biomass is a source of energy developed from organic materials such as wood, agricultural residue, and waste (WBDG 2016). Heat is released through the burning of biomass, which may be burned directly--mainly in the form of wood pellets or pine chips--or after the biomass has been converted to fuel (EIAa 2019). Biomass is renewable and sustainable when waste materials are used.
The default share of biomass heating is set at .Once biomass (such as trees) is grown specifically for heating, both land use emissions and time required for growth have to be taken into consideration. Thus, the 'realistic' limit for biomass heating is fairly low at global contribution.
Biomass may be considered carbon neutral since its source plants capture almost the same amounts of CO2 that the production and burning of biomass emit (EIAb 2019). Combustion of biomass for heating of buildings is estimated to emit 38 kg CO2 eq/MWh heat (FRUK 2019).
Geothermal heating is a direct use of the geothermal energy stored in the earth. It is an efficient process that entails the movement of heat absorbed from the earth and transferred into buildings.
The projected default share of geothermal heating is set at , which can be reasonably increased to . Geothermal heating is considered a renewable source of energy, and is estimated to emit 14 kgCO2 eq/MWh of heat (McCay 2019).
Natural gas is a fossil fuel trapped in and extracted from below the Earth's surface. In a natural gas burner, water is heated, pumped through a metal coil to heat air, and the air is blown through ducts to provide space heating (CAPP 2019).
The projected default share of natural gas heating is set at , which can be reasonably increased to . Direct emissions are estimated to be 227 kg CO2 eq/MWh heat in buildings (FRUK 2019).
Because natural gas is burned at the location of the building that is heated, capture and storage of the direct emissions are not feasible.The "capturable" emissions from this heating type are assumed to be the emissions in production of natural gas. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from this fuel type.
Oil is a fossil fuel combusted in boilers and furnaces to heat and pump water. The projected default share of oil heating is set at . Direct emissions from the combustion of oil are estimated to be 244 kg CO2 eq/MWh heat, and lifecycle emissions are estimated to be 314 kg CO2 eq/MWh heat in buildings (FRUK2019).
Because oil is typically burned at the location of the building that is heated, capture and storage of the direct emissions are not feasible.The "capturable" emissions from this heating type are assumed to be the emissions in production of oil. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from this fuel type.
Minimizing heating emissions in buildings includes solutions like converting solar energy into thermal and increasing heating efficiency with heat pumps (DrawdownHP 2020). Another solution to reducing heating emissions efficiently includes switching to a district heating system, which is a centralized plant of underground pipes that are able to provide heating to multiple buildings (DrawdownDH 2020).
The projected default share of other heating is set at . Because the adoption of heat pumps and solar thermal energy is growing quickly, electric heating sources can reasonbly be increased to . The carbon intensity used here is the carbon intensity of the electricity grid you choose in the electricity sector of this simulation.
The decrease in carbon intensity from CCS in electric heating come from the CCS in the electricity mix. Therefore, increasing the percentage of coal and natural gas electricity will increase the effect of CCS.
Coal is a carbon-rich fossil fuel burned to heat residential and commercial buildings. Although using coal for heating buildings has decreased in favour of alternative fuels, coal consumption for heating use is still on the rise in some countries (Kerimray 2017). The projected default share of coal heating is set at . Heating through burning coal is estimated to contribute 414 kg CO2 eq/MWh heat to building emissions (FRUK 2019).Direct emissions from the combustion of coal are estimated to be 341 kg CO2 eq/MWh heat, and lifecycle emissions are estimated to be 414 kg CO2 eq/MWh heat in buildings (FRUK2019).
Because coal is typically burned at the location of the building that is heated, capture and storage of the direct emissions are not feasible.The "capturable" emissions from this heating type are assumed to be the emissions in production of coal. The change in carbon intensity because of CSS is calculated as a percentage of the difference between lifecycle and direct emissions from this fuel type.
Natural gas is estimated to emit 0.8 Gt CO2 eq/year in buildings, taking up about 2% of fuel shares for space cooling in buildings (IEAb 2019).
Space cooling, or air conditioning, has recently become a leading driver for electricity demand with an increase of about 5% in 2017 (IEAb 2019). Electricity for air conditioning is fuelled largely by fossil fuels, with an estimated 2.7 Gt CO2 eq/year in buildings emissions for coal, while natural gas has an estimated 0.8 Gt CO2 eq/year in buildings emissions.
The cement sector holds the second largest share of industrial CO2 emissions at 27%. Carbon emissions considered here arise from the chemical reaction in cement hardening, which releases carbon dioxide. Up to 43% of these emissions may be reabsorbed by the cement over its lifetime, which is not included here.
Clinker is the binding ingredient in the production of concrete, which allows the cement to harden in reaction to water. For each additional percentage of substituting conventional clinker with materials such as volcanic ash, finely ground limestone, and fly ash, it is estimated that per year is saved (DrawdownC 2020). The projected default substitution of alternative materials in the composition of cement is —increasing this to is considered to be reasonable (DrawdownC 2020).
Refrigerants are substances that absorb and release heat in cooling systems, such as refrigerators and air conditioning, with the use of compressors and evaporators. CFCs and HCFCs used to be the main refrigerants, which have been effectively phased out by the Montreal Protocol restricting the release of these gases into our atmosphere (IPCC 2014). The ability of CFCs and HCFCs to break down ozone was a major contributor to the formation of the ozone hole. HFCs have replaced CFCs and HCFCs as most common refrigerant. While HFCs are not ozone-depleting, they are strong greenhouse gas that don't naturally occur on Earth, with an emissions growth rate of 10-15% each year (CCAC 2016).
Mitigation of HFC emissions includes proper lifetime management (leak management), refrigerant recovery and disposal, and substituting HFCs with alternative, naturally occurring refrigerants, such as ammonia and propane. (IPCC 2014, Drawdown RM 2019)
HFC emissions are estimated to be 8.8 GtCO2 eq/year in 2050 (EPA 2009). The projected default reduction of HFC emissions is set at —decreasing this to is considered to be reasonable (DrawdownAR 2020).
Freight transport is another steadily growing sector (ITF 2017). We estimate the annual total goods shipped per-person in 2050 to be , assuming a population of 9.7 billion (ITF 2019). Your population prediction on the common sliders is then used to calculate the total amount of goods shipped in 2050. Shipping is considered to be the international (maritime and aviation) and intranational (road and rail) transport of goods. Each type of transport is assumed to have the 2050 shares: 75.8% by sea, 17% by road, 7% by train, and 0.2% by air.
Global freight shipping by road is increasing, accounting for about 6% of GHG emissions (Drawdown T 2019). The main mitigation strategy for decreasing road shipping emissions is adopting more fuel efficient technologies for freight trucks. The carbon intensity of road shipping is estimated to be (CN 2019). Decreasing this to is considered to be reasonable (ECTA 2011).
Rail shipping accounts for the transport of 12 billion tons of freight per year (Drawdown R 2019). Mitigation strategies for rail shipping include improving train fuel and operational efficiency and the electrification of railways. The carbon intensity of rail shipping is estimated to be (CN 2019). Decreasing this to is considered to be reasonable as electric trains increase along with renewable energy (Drawdown R 2019).
Maritime shipping accounts for 75.8% of shipping and 3% of global GHG emissions (ITF 2019). Through design and technology replacement, increasing ship efficiency and less fuel-intensive shipping are the main mitigation strategies for shipping by sea (Drawdown S 2019). The carbon intensity of maritime shipping is estimated to be (CN 2019). Decreasing this to is considered to be reasonable (Walsh 2011).
Emissions from air transport are estimated to be 2-3 times higher impact in relation to ground transport because of close proximity to the atmosphere (TFC 2019). Fuel efficiency is the main mitigation strategy for reducing the GHG emissions of airplanes (Drawdown Air 2019). The carbon intensity of shipping by air is estimated to be (Howitt 2011). Decreasing this to is considered to be reasonable (TFC 2019).
The following approximate area sizes are used for this estimation:
|The United Kingdom||200,000|
|Prince Edward Island||5,000|