Climate & lifestyle report

Please note this page was last updated in 2020. While our overall views remain unchanged, some details may be out of date.

Advice on how to live a climate-friendly lifestyle is typically dominated by adjectives rather than numbers. We might, for example, be told that reusing plastic bags and switching to a plant-based diet have a huge effect on the climate. Such adjectives provide no indication of scale and so do not tell us which of our lifestyle decisions can make the biggest difference. Where numbers are used, they invite a focus on the trivial. For example, the BBC advises us that if phone chargers were unplugged when not in use, “the UK could save enough electricity each year to power 115,000 homes”.¹ Numbers like these provide no indication of scale. In fact, all the energy saved by unplugging a phone charger for a day is used up in one second of car driving.² Unplugging the phone charger is undoubtedly worthwhile, but is rather like bailing out a sinking ship with a teaspoon.

All of this demonstrates the importance of quantitative comparisons and of focusing on big wins. In this report, we quantify the scale of the environmental impact of different lifestyle choices and then draw up a handful of general principles and heuristics for the climate-conscious individual. Given that we have limited attention, it is best to focus on the choices that make the biggest difference, rather than on minute precise comparisons between inconsequential decisions.

What we are saying:

1. Donations are a complement to lifestyle choices: Donations to effective climate charities provide an excellent complement to more conventional lifestyle changes such as flying less, eating less meat, etc.
2. Huge differences in impact: When we think about different lifestyle choices, there are huge differences in impact. It is important to be broadly aware of this to have the most positive effect through lifestyle changes.
3. Policy matters for lifestyle choices: In many industrialised economies, there are now an increasing set of climate targets and policies that do affect the impact of lifestyle choices. This is a good thing because it makes target achievement less dependent on everyone being voluntarily virtuous. But it also means this is something we need to take into account when considering which lifestyle changes to implement.

What we are not saying:

1. We are not denying individual responsibility: We are not saying that policy and the opportunity to donate negate individual responsibility for lifestyle decisions. Rather, we are seeking to expand the actions pursued by climate conscious individuals.
2. Donations are not offsets: We are not saying that donation is a form of offsetting. Rather, it is a form of increasing impact; indeed we think that the mindset of offsetting artificially limits our ambition far beyond what it could be.
3. We are not saying that you should or shouldn’t have children: We mostly discuss this example since it has been discussed heavily in prior work and we believe prior analyses have significantly overstated the impact of this choice.
4. We are not claiming that our estimates are 100% precise: Our estimates -- in particular with regards to policy -- should not be taken as exactly precise, as there are different assumptions and uncertainties flowing into the analysis. Rather, they should be taken as indicative to give a sense of how policy changes the picture.

How much does the typical person emit?

For context, it is useful first to understand how much CO2 the average person emits. Figure 1 shows emissions per person in countries with the most Founders Pledge members. These emissions are consumption-based, and so account for emissions-intensive imports. To calculate consumption-based emissions we need to track which goods are traded across the world, and whenever a good was imported, we need to include all CO2 emissions that were emitted in its production, and vice versa to subtract all CO2 emissions that were emitted in the production of goods that were exported.

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

One important source of emissions not included in these estimates is international travel. For example, the average Swede is estimated to emit around 1 tonne of CO2 through international flights.³ This is likely a useful approximation of the effect of air travel on people's emissions in other rich countries.

As Figure 1 shows, emissions per person vary considerably even across rich countries: the average American emits 18 tonnes of CO2 per year, whereas the average Swede emits only 7 tonnes of CO2 per year. This variation is explained mainly by differences in how far people in these countries drive, and the extent to which they rely on fossil fuels to produce electricity and heat. The disparity in per person emissions is most stark between rich and poor countries, with the average Indian emitting less than a tenth of the average American or Canadian. Monthly emissions per person in rich countries are usually higher than yearly emissions per person in the poorest countries.⁴

So, as a guiding rule:

The tiny contributions of every individual add up to a huge global problem. Global average emissions are 5 tonnes of CO2 per year, which, when spread across 7 billion people, means we are putting about 35 billion tonnes of CO2 into the atmosphere every year. Emissions have risen unchecked since the Industrial Revolution, and there is not yet any sign of a major course correction.⁵

Summary: key takeaways

Figure 2 below shows the effect of different lifestyle decisions, ignoring the effects of government policy:

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

This suggests that decisions about whether to have a child are completely dominant from the point of view of the climate. However, the estimates above assume that the emissions of one's descendants will continue at a constant rate into the future, which is highly unrealistic given (1) emissions per head are trending downward in most advanced economies, and (2) many jurisdictions have legally binding climate targets and/or carbon pricing schemes that commit them to decarbonization, in some or all sectors, in the next few decades. These include:

• The EU
• The UK
• Switzerland
• California
• Ten north-eastern states in the US — Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont — that make up the Regional Greenhouse Gas Initiative (RGGI)

These jurisdictions have all put more or less binding caps on their emissions from electricity and, in most cases, several other sectors such as industry. This has a huge effect not only on the emissions effect of having children, but also on the other lifestyle decisions. In a system with a firm cap on total emissions, if you increase demand for coal-powered electricity, then you would increase demand for emissions allowances, but given the overall limit set, this would necessarily lead to emissions reductions somewhere else, leaving overall emissions unaffected. This is known in the literature as the 'waterbed effect'. Moreover, many of these jurisdictions also have legally binding climate targets. For example, the UK has introduced a law to reduce carbon emissions to near zero by 2050.

Figure 3 summarizes how estimates change when taking policy into account, with the dark bars providing a more accurate picture if you live somewhere with strong climate policy.

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

The biggest discrepancy here concerns the climate effect of having children. For the reasons given, we think our estimate of the effect of having children is more accurate for people living in the EU or US states with strong climate policy, such as California, New York, as well as other states in the Northeast. Indeed, even outside the US states with strong climate policy, we think the estimate accounting for policy is much closer to the truth, since emissions per head are also declining at the national level, and climate policy is likely to strengthen across the US in the next few decades.

Note that this is fundamentally a good thing. Rather than relying on the virtuous behavior of hundreds of millions of individuals across a wide range of daily choices, political targets and implemented policies can ensure that climate targets are reached. For reasons of flow, we discuss the question of how doubts about climate targets being met affect our analysis in the Appendix.

Figure 4 shows the effect of policy on other key lifestyle decisions, excluding children:

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

As this shows, once we take account of policy: some decisions, such as switching to an electric car, increase in impact; others, such as buying green electricity and flying within the EU, are much less impactful than they first appeared; and some are unaffected.

Trade-offs

It is important to note that some of these choices involve major trade-offs: these are not all-things-considered judgements about the desirability of these actions. For example, having children produces benefits as well as costs, and we should consider these benefits and costs holistically, rather than focusing on only one negative effect children have (CO2 emissions). A deep retrofit of an energy inefficient house would be very expensive, and the money spent could be donated to effective charities. This said, many key lifestyle choices, such as switching to an electric car or reducing unnecessary flying, driving, or other forms of consumption, do not involve great sacrifice.

Personal donations

Figure 3 excludes one crucial lifestyle choice: personal donations. Our research suggests that our recommended climate charities have in the past averted a tonne of CO2 for less than $10 in expectation, and potentially much less. It is important to stress that we think there is a very large gap in impact between the very best charities and the typical charity - our research across a range of causes areas has shown that you can often 100x impact by supporting the very best charities. Therefore, choosing carefully when donating is essential.

The potential impact of your personal donations is much larger than the lifestyle decisions discussed above:

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

However, we strongly emphasize that, for reasons we explain below, this does not mean that donations to effective climate charities offset your emissions.

Moreover, a focus on offsetting arbitrarily limits people's ambitions, leading people to ask: how can I undo the effect of my own emissions? Instead, we believe that people should ask: how can I make the biggest possible impact on the climate? A typical person emits 5-20 tonnes of CO2 each year, so if you assume that the most effective climate charities can abate a tonne of CO2 for less than $10, then on the offsetting approach, the most you could donate would be $200 per year. Our recommended charities operate on budgets in the low millions but have led policy campaigns that have had a huge effect on global climate policy. Many people in wealthy countries have the capacity to provide large and sustained support to these charities, and thereby have enormous leverage. Personal donations are by far the biggest lever that individuals can have on the climate, and should be a top priority for climate-conscious individuals.

Another potential avenue of climate impact is direct activism and voting. Like donations, voting and political activism affect emissions far beyond your own consumption, so it is plausible that it will also have a much larger effect. We have not investigated these for this report, but they are worthy of consideration.

With this clarified, we now discuss our main findings in more detail.

Children

The ethics of having children is controversial, but needs to be discussed. Figure 2 suggests that decisions about whether to have children are much more important for the climate than all other lifestyle decisions. There is some disagreement about how to calculate the climate effects of having a child. Since we are interested in counterfactual impact, i.e. making the world better than it would otherwise have been, we believe the correct way to calculate this is to compare the world in which you have a child to the world in which you do not. That is, we have to compare these two worlds:

World without child: No emissions from children, grandchildren, great grandchildren etc.
World with child: All of the emissions from your children, grandchildren, etc.

One concern with this method of calculating emissions is that it double counts the emissions of parents and children. However, we do not believe this to be a flaw. This shows that the counterfactual emissions of the parent and the child, taken individually, cannot be aggregated, not that this is the wrong way to calculate their counterfactual impact, taken individually.⁶

The overall climate effect of your decision to have children depends on where you live. This is for several reasons. Firstly, as we saw above, current emissions per person vary greatly depending on where you live, with the typical French person emitting 7 tonnes of CO2 and the typical American emitting 18 tonnes of CO2 per year.

Secondly, many rich countries, such as the UK, are legally required to get to net zero emissions by 2050, and other EU states are moving in that direction. If they succeed, then the climate effects of your procreative decision will, at least for domestic emissions, stop there. Many US states, including California, New York and other states across the North East have climate plans in place to reduce emissions by 80% or more by 2050 (compared to 1990), making them fairly similar to European countries in terms of emissions trajectories. For the US as a whole, given weaker climate policy than in Europe, we assume it to decarbonize much later (our model assumes that the US will decarbonize in 2080).

Thirdly, many regions have placed more or less binding caps on emissions from electricity and, in many cases, other sectors such as industry. This includes:

• The EU
• The UK
• Switzerland
• California
• Ten north-eastern states in the US — Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont — that make up the Regional Greenhouse Gas Initiative (RGGI)

In a system with a firm binding cap on emissions, having a child who consumes polluting electricity would increase demand for emissions allowances, but this would necessarily lead to emissions reductions somewhere else, leaving overall emissions unaffected. This is known as the "waterbed effect" in the literature: if you push down emissions in one place, they pop up elsewhere, and vice versa.

The situation is somewhat complicated because recent institutional changes in carbon markets have introduced more flexibility to stay below or exceed emissions caps under specified circumstances. This means that the waterbed effect has been partly nullified in some places. For example, in the world's largest operational carbon market, the EU Emissions Trading Scheme, it is estimated that 1 tonne of CO2 avoided only leads to a saving of 0.4 tonnes of CO2, though if current policy remains, the waterbed effect will return completely by 2023, meaning that individuals cannot affect emissions in covered sectors.⁷ The extent to which the waterbed effect applies in California is less well-studied, but the cap is not completely firm,⁸ which leaves some room for the impact of behavioral change, even though it is likely weakened.

Thus, over a child's lifetime, they will likely not affect emissions from electricity, which in the places mentioned is around 20-25% of emissions, or at least the effect will be reduced through policy. As more jurisdictions impose carbon prices and more sectors are included in existing carbon markets, such as domestic heating and road transport, it will be harder and harder for a child to have any direct effect on the climate: they will merely increase demand for emissions allowances, which will reduce emissions elsewhere.

Indeed, it seems likely that many more jurisdictions in the EU will take other further actions that could drastically limit the potential climate effect of having a child. For example, from 2035, polluting cars will be banned in the UK, and this is likely to happen across the entire EU in the next few decades. Moreover, many jurisdictions already set binding periodic climate targets covering all domestically produced emissions. For instance, the UK has five yearly carbon budgets. If these budgets are binding, then having an additional child who emits CO2 merely means that the UK has to work harder to reduce emissions elsewhere. If the UK government is committed to its legally binding climate targets, then new British children cannot have any effect on the climate through domestic emissions.⁹

All in all, we think it likely that, wherever you live, climate policy will get considerably more stringent over the course of your descendants' lifetime, which has a large effect on the potential impact of having a child. Our model tries to roughly account for all of these uncertain factors. Once we take them into account, our estimate of the effect of having a child is drastically lower than other estimates. Wynes and Nicholas (2017) estimate that the average effect of having a child is an additional 60 tonnes of CO2 per year. In contrast, our estimates suggest that the true figure is closer to 4 tonnes of CO2 per year.

Note, again, that this is a good thing -- it means that policies can ensure climate progress rather than relying on the voluntary virtuous behavior of millions of citizens across a multitude of daily decisions.

Even on these drastically reduced estimates, having a child causes substantial emissions. However, we think that it would be too hasty to conclude that you should not have children because of these costs to the climate. Children produce benefits as well as costs.¹⁰ Presumably, bringing people into existence benefits them, otherwise we would have to say of every living person that it would not matter to them if they had never existed.¹¹ Moreover, children enhance the lives of other people by being good sons, daughters, friends and citizens. At least in growing economies that have escaped the Malthusian trap, over the course of their life, children also produce net economic benefits. If they did not, then we would expect exploding population to be associated with ever-expanding misery, but this is the opposite of what we have observed.¹² It also needs to be borne in mind that children can vote, engage in activism and donate to effective climate non-profits. As we discuss in section 8, the impact they can have through donating far exceeds the impact they could have through lifestyle choices. This means that the decision about whether to have children involves trade-offs: they will impose some costs in terms of CO2 emissions, but would also bring various benefits.

Moreover, note that even in a US state without strong policy (the highest case we consider), having a child produces about an extra 16 tonnes of CO2 per year, and as we will see below it plausibly costs less than $10 per tonne to abate a tonne of CO2. Thus, it would cost $160 per year to negate the climate effects of having a child - a trivial sum compared to the other costs of raising a child. We discuss issues around offsetting in section 8.

Travel

Decisions about whether to walk, cycle, drive or fly are hugely important for individual carbon emissions.

Petrol, hybrid or electric?

The ground-breaking work of Tesla and the shift away from the internal combustion engine it may have inspired seem unambiguously good for the climate. But some question whether hybrid cars and electric cars are better than petrol cars once we take into account two factors:¹³

• The emissions involved in making the batteries, which mean that hybrids and electric cars produce more emissions in construction than petrol or diesel cars.
• The emissions produced when charging a plug-in car, which can be substantial if, as in almost all countries, the grid is predominantly powered by fossil fuels.

Figure 6 shows one estimate of the lifecycle emissions (i.e. including emissions from producing the car and from driving) of different types of car, assuming that electric cars are charged from the US grid (currently 32% gas, 30% coal, 20% nuclear, and the remainder mainly hydro and wind). It shows that:

Electric vehicles (yellow squares) are better than hybrids (pink diamonds), which are better than diesels (grey circles), which are better than petrol cars (black circles).

Source: Miotti et al, ‘Personal Vehicles Evaluated against Climate Change Mitigation Targets’, Environmental Science & Technology (2016)

Other research produces similar findings.¹⁴ Wynes and Nicholas (2017) find that you can reduce your emissions from driving from 2.4 tonnes to 1.4 tonnes by switching to an electric car. These benefits are likely to increase as advanced economies trend towards power-sector decarbonization. By going completely car-free, you could reduce your emissions by around 2.4 tonnes.¹⁵ This suggests that there are large environmental benefits to be had from living in cycle-friendly urban centers with good public transport, instead of in suburbs.

However, as before, this analysis fails to account for the effect of policy, which in this case increases the climate benefits of switching to an electric car compared to what we might naively have thought. It is commonly argued that if you live in a place with a coal-reliant grid such as Poland or Germany, an electric car is really a coal-powered car. However, this neglects the 'waterbed effect' mentioned in section 3. Many regions have placed more or less binding caps on emissions from electricity. In a system with a firm binding cap, charging an electric car off a coal- powered grid would effectively be zero carbon. The coal-powered car would increase demand for emissions allowances, but given the overall limit set, this would necessarily lead to emissions reductions somewhere else, leaving overall emissions unaffected. In the EU, the waterbed effect erodes 60% of the effect of increased electricity consumption, declining to 100% in a few years' time.

Since carbon caps are in many places present in the electric sector but not in the road transport sector, switching to electric cars is more impactful than we might previously have thought because the climate effect of charging your electric car off the electric grid is largely negated. Thus, if you live somewhere with binding carbon markets, then the climate effect of your electric car largely comes from producing the vehicle, which is only around one fifth of the emissions from battery-powered vehicles.¹⁶ This doubles the climate benefits of switching to an electric car, increasing emissions reductions from around 1 tonne of CO2 to 2 tonnes of CO2.

Secondly, for people living outside jurisdictions with a binding cap on electricity emissions, it is important to consider the carbon intensity of electricity, which varies widely across jurisdictions, by more than a factor of 10 in some cases. You can check the carbon intensity of the grid where you live with this great interactive map.

One other key takeaway is that given the substantial emissions involved in making cars, you should have as few cars as possible: it would be no good having one petrol car as well as an electric car that you rarely drive.

Flying

Decisions about whether and how to fly are one of the most important individuals will make from the point of view of the climate. Just one round-trip transatlantic flight contributes 1.6 tonnes of CO2, or nearly a quarter of the annual emissions of the average Swede.¹⁷ Decisions about whether to fly economy or business class also have a big effect.

The evidence suggests that:

The reason for this is that flying premium takes up more square footage on the plane, which means that fewer people overall can travel on the plane. Moreover, because premium tickets are upwards of 3 times more expensive than economy tickets, premium passengers cross-subsidize the travel of economy passengers, increasing overall demand for air travel. According to a World Bank study, as a rough rule of thumb:

• Flying business produces 2-3x as much CO2 as flying economy.
• Flying first class produces 2-3x as much CO2 as flying business.¹⁸

Therefore, flying business on a round-trip transatlantic flight will produce upwards of 3 tonnes of CO2, and flying first class would produce upwards of 6 tonnes of CO2, nearly the entire annual emissions of the average Swede. Given the environmental costs of flying, finding low-cost ways to reduce flying would be highly beneficial.

Again, however, the "simple" direct environmental effects of flying are affected by existing policies. Within-EU flights are covered by the same emissions trading system discussed before, the EU Emissions Trading Scheme. As discussed above, this means that a tonne of CO2 avoided from a within-EU flight in fact averts 0.4 tonnes, and this might decline to zero -- meaning you cannot affect net EU emissions through your flight decisions -- in the next few years (due to the waterbed effect).

For non-within-EU flights, the impact of flying is as suggested above. However, in 2016, the International Civil Aviation Organization adopted the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). CORSIA aims to stabilize net CO2 emissions from international civil aviation at 2020 levels through efficiency improvements and through carbon offsets. Provided the offsets are quality assured, this would erode the potential impact of abstaining from flying. Until that system has been set up and shown to be effective, it would be premature to let this program figure too firmly in our decisions about whether to fly.

Green electricity

Buying green electricity has been estimated to save between 0-3 tonnes of CO2, depending on where you live. Thus, in many countries, buying green electricity appears to be a good way to reduce your CO2 emissions. The argument goes that buying green electricity would reduce emissions by (1) increasing demand for renewable electricity, (2) leading to higher renewable generation (3) reducing demand for high-carbon electricity, such as coal, and (4) leading to lower high carbon generation overall. However, this again neglects the effect of policy, which arguably completely nullifies any counterfactual effect on the carbon emissions from buying green electricity. Firstly, as discussed above, for people living in capped emissions trading regimes, buying polluting electricity merely means that someone else in the jurisdiction has to emit less. As mentioned, in the EU, this offsets around 60% of the effect of transferring to green electricity in the EU, potentially increasing to 100% in the next few years.

Secondly, many countries and regions have support policies that mandate specific shares or amounts of renewable energy generating capacity. For example, California mandates that 50% of California's electricity should be powered by renewable resources by 2025, and Germany even aims for 65% by 2030. The supply of renewables is usually mainly driven by these political requirements rather than consumer demand.

Thirdly, hurdles around greater penetration of renewables tend to revolve around local opposition and grid and storage infrastructure, not a lack of consumer demand for renewable electricity. For example, in Germany, a country where popular and policy support for renewables is among the highest in the world, local opposition to grid infrastructure and onshore wind turbines has led to a near standstill of additional onshore wind capacity.¹⁹ It is therefore unlikely that green electricity contracts have a substantial effect on renewables expansion.

Fourthly, insofar as green electricity contracts for consumers are realized through buying traded green electricity certificates, it is very likely that one just buys certificates from large, already existing renewable capacities, for example Norwegian hydropower, without affecting renewables supply at all. Indeed, this is the main conclusion of the paper Wynes and Nicholas cite for the UK (with an effect close to zero), with the original paper citing Germany and Finland as other cases where this is true.²⁰

Overall, for people living in jurisdictions with advanced climate policies, political factors greatly reduce the effect you can have through buying green electricity. Given the factors laid out above, we would expect this to nullify almost all of the effect of buying green electricity for jurisdictions with strong climate policy.

Green heating

In most industrialized countries in the Northern hemisphere, heating is the dominant consideration for domestic energy consumption. In the EU, heating living space and water together account for about 80% of residential energy consumption, primarily from fossil fuels.²¹ Emissions from domestic heating are around 2.3 tonnes per household in the UK,²² which is at the higher end compared to Europe and the US because the UK is cold and the housing stock is of low quality and so has poor energy efficiency.

There is some low-hanging fruit for people in energy inefficient homes, such as double glazing and loft insulation. In the UK, these would avert around half a tonne of CO2 and save the average gas heated home £184 per year.²³ However, reducing domestic heat consumption by up to 80% through a 'deep retrofit' is an involved endeavor, involving large upfront costs, with costs in the region of $15,000 for a typical UK home.²⁴ These would take at least 10 years to pay back in the form of reduced energy bills.²⁵

In some places, there may also be scope to switch to low carbon heat sources, such as district heating, biogas, solar thermal or electric heaters. However, biogas, district heating, and low-carbon electricity are only available in some locations. In the UK, electric heating is more expensive than gas heating adding about 50% to your heating costs,²⁶ which is money that could be donated to effective climate non-profits.

Again, we also need to consider the effect that policy has on the potential impact of these choices. Firstly, in jurisdictions with caps on carbon emissions from electricity but not on emissions from residential heating systems (such as the EU), switching to electric heating has greater climate benefit than one might naively have thought, for the reasons outlined above: increasing demand for polluting electricity merely means that someone else in the system has to emit less.

Secondly, some carbon markets, most notably California's cap and trade scheme, include domestic heating under the cap. Thus, the waterbed effect kicks in again, nullifying some of the effect you could have by switching to green heat sources. However, the EU Emissions Trading Scheme does not include domestic heating systems, so there is more scope for personal impact in the EU.

Meat

Assessing the climate impact of dietary choice is challenging because different animals put different types of greenhouse gases into the atmosphere -- methane and nitrous oxide, as well as CO2 -- and it is difficult to know how to compare the long-term effect of these different gases. Methane is removed from the atmosphere after around 12 years, but over 20 years, a tonne of methane produces 84x as much warming as a tonne of CO2. However, around 40% of CO2 emitted today persists in the atmosphere for more than 1,000 years, so CO2 poses more of a long-term challenge than methane. Figure 7 depicts this difference.

Source: Allen et al, ' New use of global warming potentials to compare cumulative and short-lived climate pollutants', Nature Climate Change, (2016).

Many climate scientists use a version of a metric called CO2-equivalent with Global Warming Potential 100 (CO2e GWP100) which says that, over a century, a tonne of methane emitted today has 25x as much warming effect as a tonne of CO2. However, we agree with a dissenting set of physicists that this version of the CO2e metric overstates the effect of methane relative to CO2 and that CO2 and other long-lived climate pollutants such as nitrous oxide are much more important than methane from a climate point of view. The reasons for this are outlined in Short-Lived Promise? by the Oxford physicist Myles Allen, and concern the effect that short-lived climate pollutants can have on peak warming.

This is important because it has a large effect on estimates of the climate impact of dietary choices. Ruminants like cows produce large amounts of methane (mainly by belching). On the standard 25x weight for methane, methane accounts for 50-80% of the climate impact of beef consumption.²⁷ On this metric, decisions about beef consumptions are crucial: per calorie, beef produces 5x as much CO2e as dairy, chicken, fish, pork and eggs.²⁸ However, if you take our preferred metric of focusing solely on long-lived climate pollutants like CO2 and nitrous oxide, the picture is very different: beef only produces 2x as much CO2e as dairy, chicken, fish, pork and eggs. On this view, the emissions from food mainly stem from deforestation and the emissions involved in growing animal feed.

Moreover, as a result of this, the estimated emissions gained from switching to a plant-based diet are much smaller than many estimates. On our estimates, switching to a plant-based diet reduces your emissions by 0.4 tonnes of CO2e per year, whereas other estimates suggest an effect twice as large.²⁹ Nonetheless, switching to a plant-based diet remains much more impactful than other dietary choices, such as eating organic food, which is probably worse for the climate than conventional food because it uses more land.³⁰

Climate impacts aside, the overall merits of cutting out certain kinds of meat depends on what food you switch to. Switching to a plant-based diet seems to be an unalloyed good due to the improvements in animal welfare. However, switching from beef to dairy, eggs, chicken or fish probably increases the impact on animal welfare relative to beef because cows seem to have much better lives than farmed chickens or fish (though of course it is extremely difficult to estimate the difference).³¹ Indeed, the life of a factory farmed chicken is so horrific that the climate benefits of shifting from beef to chicken could easily be outweighed.³²

Personal donations

One personal decision that many people do not consider when deciding how they can have an impact on the climate is personal donations to effective climate charities. On our estimates, the potential impact of donating to effective climate charities dwarfs the effect of other lifestyle decisions. However, this does not mean that such donations offset any harm you might have done by emitting CO2. Moreover, a focus on offsetting unnecessarily limits people's ambitions, and drastically limits the potential effect people can have on the climate.

Ethics and offsetting

The acceptability of offsetting depends on which ethical theory is correct. The two main contenders in moral philosophy are rights-based and consequentialist ethical theories. We will argue that neither theory entails that, in almost all normal circumstances, (1) donations to climate charities offset your other emissions, or (2) you are morally required to donate to climate charities because you have emitted in the past.

Consider first the rights-based view of offsetting. Some argue that carbon offsetting is akin to infidelity offsetting, i.e. cheating on your partner and then offsetting this by paying someone else to not to cheat on theirs.³³ Even though the net total amount of infidelity is zero, cheating on your partner and then offsetting is still wrong because someone has been harmed, and your offset does not undo this harm. Carbon offsetting is unjust for the same reason. This argument could be grounded in the idea that people have a right not to be harmed by carbon emissions.

This argument only works in certain conditions.³⁴ If you emit carbon throughout your life and offset at exactly the same time, no-one is harmed in the world in which you offset compared to the world in which you emit nothing in the first place. It is the equivalent of never committing adultery in the first place.

However, it is very unlikely that any offsetting scheme you fund will offset your carbon at exactly the same time as you emit. This especially true if you donate to high-risk/high-reward policy charities. Let's compare two worlds: Offset and No Emissions.

Offset: You emit 1 tonne of CO2 and offset 1 tonne of CO2 one month later No Emissions: You do not emit any CO2.

Both of these worlds are very nearly equally good because they each have equal amount of cumulative CO2 emissions (and that is what determines peak warming). However, in Offset, the CO2 you initially emit does harm people by causing warming. Even though you reduce emissions one month later, this harm has still been done: the person made worse-off by your initial emission is still worse-off than they would have been if you had never emitted. This is indeed like committing adultery and then paying someone else not to commit adultery.³⁵

It is worth noting that the rights-based ethical theory is extremely strict with respect to carbon emissions and other forms of pollution: it requires that no-one should emit any CO2 or do anything that risks harming anyone, even if they produce other benefits while doing so.³⁶ For example, it would imply that a politician is not permitted to fly to pivotal global climate talks, even if doing so would allow them to negotiate a binding global climate treaty.

Other ethical views, such as consequentialism, are less strict in this respect. Consequentialism says that we ought to do whatever does the most good, or produces the best consequences. If a politician can do more good by flying to the climate conference than not going at all, then she ought to do so. However, consequentialism says there is no special reason to offset the harm that you have done in the past. Suppose that you have emitted a tonne of CO2 and you now have to decide what to do with $1,000. Consequentialism says that you ought to do whatever produces the most good, impartially conceived: if that is donating to a malaria charity and not a climate one, then you ought to donate to the malaria charity regardless of whether you have emitted CO2 in the past. In short, on consequentialism, offsetting is irrelevant.

In sum, it is not usually feasible to truly offset the harm from your past emissions. So, on rights-based views, donations to climate charities are irrelevant with respect to offsetting your harm. On consequentialist theories, offsetting is always irrelevant, and we should instead try to do the most good.

The limited ambition of offsetting

This clarified, the main problem with offsetting is that it limits people's ambitions, leading people to ask: how can I undo the effect of my own emissions? Instead, people should ask: how can I make the biggest possible impact on the climate?

If we only donate to offset our personal emissions and no further, then we hugely restrict our own potential impact. A typical person emits 5-20 tonnes of CO2. If you assume that the most effective climate charities can abate a tonne of CO2 for $10, then on the offsetting approach, the most you could donate would be $200 per year. But many people in rich countries have the capacity to make large and sustained funding commitments to the very best climate charities, which offers enormous leverage. Our two recommended climate charities, the Clean Air Task Force and the Coalition for Rainforest Nations, each have annual budgets of less than $8 million per year. For this relatively small amount, they have each played a leading role in political campaigns which have had a huge effect on global climate policy.

This being said, when donating, it is very important to choose carefully. Many organizations offer surprisingly cheap high-confidence carbon offsets, promising to abate a tonne of CO2 with high confidence for $1 or even less. These figures are not realistic. The incentives are not set up well for organizations to provide assured carbon emissions reductions. There is limited oversight of the work done by offsetting organizations, so they have an incentive to offer attractive price points, but not to provide assured emissions reductions. Thus, choosing carefully and donating to effective policy organizations is crucial, plausibly offering 100x impact multipliers.

Figure 8 shows the impact your donations can have relative to other lifestyle decisions.

Source: See the references and calculations in the Climate and Lifestyle calculations sheet

Personal donations are by far the biggest lever that individuals have on the climate, and should be a top priority for climate-conscious individuals.

Acknowledgment: Thanks to Dominic Roser for providing valuable feedback on this report; all errors are ours.

Appendix: But, are climate targets credible?

Of course, when discussing climate targets affecting the effect of lifestyle changes, one might wonder whether policy targets are credible, or just easily missed -- thereby again increasing the importance of lifestyle changes.

There are three responses to this:

Firstly, jurisdictions that set themselves ambitious climate targets tend to achieve them or, if not, the failure to achieve interim targets at least creates strong political pressure to correct course. This is no coincidence as the presence of strong climate targets is often the result of powerful environmentalist constituencies.

Secondly, climate targets need to be missed very significantly to change our conclusions. E.g. even when assuming the US will only decarbonize by 2080, a full 30 years after the goal of international climate policy, then the emissions of an additional child are still only by about 16 tonnes per year, equivalent to a yearly donation of $160 (see below for details).

Thirdly, if one worries about targets being met, the case for political action -- of which donations to effective climate charities are an important and neglected component -- becomes even stronger. Indeed, it is precisely because target achievement is not certain that philanthropy for effective climate charities is so important and impactful.

Notes

1. BBC, How You Can Save Energy, January 4, 2008, http://news.bbc.co.uk/1/hi/business/6076658.stm. ↩

2. David MacKay, Sustainable Energy - without the Hot Air, 2009, 68. ↩

3. https://www.sciencedirect.com/science/article/pii/S0195925517303116, own calculation to per-capita ↩

4. Hannah Ritchie and Max Roser, “CO2 and Other Greenhouse Gas Emissions,” Our World in Data, accessed October 18, 2018, https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions. ↩

5. For more on the history of climate change, see our cause report at www.founderspledge.com/research ↩

6. Other researchers calculate the effect of having a child in a different way. For example, Wynes and Nicholas use the following method: half of a child’s emissions are assigned to each parent, and one quarter of that child’s offspring (the grandchildren) and so forth. Seth Wynes and Kimberly A. Nicholas, “The Climate Mitigation Gap: Education and Government Recommendations Miss the Most Effective Individual Actions,” Environmental Research Letters 12, no. 7 (2017): 074024, https://doi.org/10.1088/1748-9326/aa7541. ↩

7. Grischa Perino, “New EU ETS Phase 4 Rules Temporarily Puncture Waterbed,” Nature Climate Change, no. 8 (2018): 262–64. ↩

8. See the overview here. ↩

9. They might have some limited effect because they increase emissions in between the time points at which targets are assessed. ↩

10. For arguments in favour of having children, see Bryan Caplan, Selfish Reasons to Have More Kids: Why Being a Great Parent Is Less Work and More Fun Than You Think, First Trade Paper Edition edition (Basic Books, 2012); Toby Ord, “Overpopulation or Underpopulation,” Is the Planet Full, 2014, 46–60. ↩

11. Michael Huemer, “In Defence of Repugnance,” Mind 117, no. 468 (October 1, 2008): 899–933, https://doi.org/10.1093/mind/fzn079. ↩

12. Max Roser, “The Short History of Global Living Conditions and Why It Matters That We Know It,” Our World in Data, accessed October 18, 2018, https://ourworldindata.org/a-history-of-global-living-conditions-in-5-charts. ↩

13. See for example Bjorn Lomborg, “Electric Car Benefits? Just Myths,” USA Today, accessed October 18, 2018, https://www.usatoday.com/story/opinion/2015/02/18/electric-car-benefits-air-myths-pollution-health-column/23641729/. ↩

14. Union of Concerned Scientists, “Cleaner Cars from Cradle to Grave: How Electric Cars Beat Gasoline Cars on Lifetime Global Warming Emissions,” 2015, https://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-exec-summary.pdf; Transport & Environment, “Electric Vehicle Life Cycle Analysis and Raw Material Availability,” October 2017, https://www.transportenvironment.org/sites/te/files/publications/2017_10_EV_LCA_briefing_final.pdf. ↩

15. Wynes and Nicholas, “The Climate Mitigation Gap.” ↩

16. Marco Miotti et al., “Personal Vehicles Evaluated against Climate Change Mitigation Targets,” Environmental Science & Technology 50, no. 20 (October 18, 2016): 10710, https://doi.org/10.1021/acs.est.6b00177. ↩

17. Wynes and Nicholas, “The Climate Mitigation Gap,” fig. 1. ↩

18. Heinrich Bofinger and John Strand, “Calculating the Carbon Footprint from Different Classes of Air Travel” (World Bank, May 2013), 15. ↩

19. “Germans Fall out of Love with Wind Power,” Financial Times, November 16, 2019. ↩

20. A. Hast, S. Syri, J. Jokiniemi, M. Huuskonen, S. Cross, "Review of green electricity products in the United Kingdom, Germany and Finland", Renewable and Sustainable Energy Reviews, Volume 42, 2015, Pages 1370-1384 ↩

21. Eurostat. ↩

22. See this infographic by the Committee on Climate Change ↩

23. See this infographic by the Committee on Climate Change ↩

24. The typical UK home is 104 square metres, and the cost of deep retrofit of a home is in the region of $150 per square metre. IPCC, Climate Change 2014: Mitigation of Climate Change: Working Group III Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2014), 691. ↩

25. Brennan Less and Iain Walker, “Deep Energy Retrofit Guidance for the Building America Solutions Center,” 2015, 17. ↩

26. See the discussion by the consumer advice service Which? ↩

27. R. T. Pierrehumbert and G. Eshel, “Climate Impact of Beef: An Analysis Considering Multiple Time Scales and Production Methods without Use of Global Warming Potentials,” Environmental Research Letters 10, no. 8 (August 2015): Table 1, https://doi.org/10.1088/1748- 9326/10/8/085002. ↩

28. Gidon Eshel et al., “Land, Irrigation Water, Greenhouse Gas, and Reactive Nitrogen Burdens of Meat, Eggs, and Dairy Production in the United States,” Proceedings of the National Academy of Sciences 111, no. 33 (August 19, 2014): 11998, https://doi.org/10.1073/pnas.1402183111. ↩

29. Wynes and Nicholas, “The Climate Mitigation Gap,” fig. 1. ↩

30. Laurence G. Smith et al., “The Greenhouse Gas Impacts of Converting Food Production in England and Wales to Organic Methods,” Nature Communications 10, no. 1 (October 22, 2019): 1–10, https://doi.org/10.1038/s41467-019-12622-7. ↩

31. See the estimates from Compassion by the Pound here, though we have not looked into these estimates. ↩

32. For more on this, see our report on animal welfare at www.founderspledge.com/research ↩

33. Pete May, “Offset Your Infidelity?,” New Statesman, accessed October 18, 2018, https://www.newstatesman.com/society/2007/05/cheatneutral-offsetting. ↩

34. William MacAskill, Doing Good Better: Effective Altruism and a Radical New Way to Make a Difference (London: Guardian Books, 2015), 173–74. ↩

35. In Offset, after both of your actions have occurred – emitting and then later offsetting – someone is harmed by the warming you emit. Even if you offset only one second later, you would still very likely affect who is affected and by how much due to butterfly effects in chaotic weather systems. ↩

36. On this, see Jackson and Smith ‘Absolutist Moral Theories and Uncertainty’, Journal of Philosophy (2006); Matt Zwolinski ‘Libertarianism and Pollution’, libertarianism.org; and David Sobel ‘Backing Away from libertarian self-ownership’ Ethics (2012) ↩