Analysis: Trump election win could add 4bn tonnes to US emissions by 2030
A victory for Donald Trump in November’s presidential election could lead to an additional 4bn tonnes of US emissions by 2030 compared with Joe Biden’s plans, Carbon Brief analysis reveals.
This extra 4bn tonnes of carbon dioxide equivalent (GtCO2e) by 2030 would cause global climate damages worth more than $900bn, based on the latest US government valuations.
For context, 4GtCO2e is equivalent to the combined annual emissions of the EU and Japan, or the combined annual total of the world’s 140 lowest-emitting countries.
Put another way, the extra 4GtCO2e from a second Trump term would negate – twice over – all of the savings from deploying wind, solar and other clean technologies around the world over the past five years.
If Trump secures a second term, the US would also very likely miss its global climate pledge by a wide margin, with emissions only falling to 28% below 2005 levels by 2030. The US’s current target under the Paris Agreement is to achieve a 50-52% reduction by 2030.
Carbon Brief’s analysis is based on an aggregation of modelling by various US research groups. It highlights the significant impact of the Biden administration’s climate policies. This includes the Inflation Reduction Act – which Trump has pledged to reverse – along with several other policies.
The findings are subject to uncertainty around economic growth, fuel and technology prices, the market response to incentives and the extent to which Trump is able to roll back Biden’s policies.
The analysis might overstate the impact Trump could have on US emissions, if some of Biden’s policies prove hard to unpick – or if subnational climate action accelerates.
Equally, it might understate Trump’s impact. For example, his pledge to “drill, baby, drill” is not included within the analysis and would likely raise US and global emissions further through the increased extraction and burning of oil, gas and coal.
Also not included are the potential for Biden to add new climate policies if he wins a second term, nor the risk that some of his policies will be weakened, delayed or hit by legal challenges.
Regardless of the precise impact, a second Trump term that successfully dismantles Biden’s climate legacy would likely end any global hopes of keeping global warming below 1.5C.
The ‘Trump effect’ on US emissions
US greenhouse gas emissions have been falling steadily since 2005, due to a combination of economic shifts, greater efficiency, the growth of renewables and a shift from coal to gas power.
Since taking office in early 2021, Biden has pledged under the Paris Agreement to accelerate that trend by cutting US emissions to 50-52% below 2005 levels in 2030 and to net-zero in 2050.
He has implemented a long list of policies – most notably the 2022 Inflation Reduction Act – to keep those targets within reach. (See: How the Biden administration is tackling warming.)
In the “Biden” scenario in the figure below (blue line), all federal climate policies currently in place or in the process of being finalised are assumed to continue. The scenario does not include any new climate policies that might be adopted after November’s election.
The administration’s current climate policies are expected to cut US emissions significantly, bringing the country close to meeting its 2030 target range. Nevertheless, a gap remains between projected emissions and those needed to meet the 2030 and 2050 targets (green).
The “Trump” scenario (red line) assumes the IRA and other key Biden administration climate policies are rolled back. It does not include further measures that Trump could take to boost fossil fuels or undermine the progress of clean energy. (See: What a second-term Trump might do.)
For both projections, the shaded area shows the range of results from six different models, with varying assumptions on economic growth, fuel costs and the price of low-carbon technologies.
In total, the analysis suggests that US greenhouse gas emissions would fall to 28% below 2005 levels by 2030 if Trump secures a second term and rolls back Biden’s policies – far short of the 50-52% target. If Biden is reelected, emissions would fall to around 43% below 2005 levels.
In the Trump scenario, annual US greenhouse gas emissions would be around 1GtCO2e higher in 2030 than under Biden, resulting in a cumulative addition of around 4GtCO2e by that year.
Based on the recently updated central estimate of the social cost of carbon from the US Environmental Protection Agency (US EPA) – which stands at some $230 per tonne of CO2 in 2030 – those 4GtCO2e of extra emissions would cause global climate damages worth more $900bn.
To put the additional emissions in context, EU greenhouse gas emissions currently stand at around 3GtCO2e per year, while Japan’s are another 1GtCO2e. If the EU meets its climate goals, then its emissions would fall to 2GtCO2e in 2030 and to below 1GtCO2e in 2040.
Only eight of the world’s nearly 200 countries have emissions that exceed 1GtCO2e per year – and 4GtCO2e is more than the combined yearly total from the 140 lowest-emitting nations.
Expressed another way, the extra 4GtCO2e would be equivalent to double all of the emissions savings secured globally, over the past five years, by deploying wind, solar, electric vehicles, nuclear and heat pumps.
Carbon Brief’s analysis highlights several key points.
First, that Biden’s climate goals for the US in 2030 and 2050 will not be met, without further policy measures after the next election.
This could include additional state-level action, which could yield an additional 4 percentage points of emissions savings by 2030. Added to the “Biden” pathway, this would take US emissions to 47% below 2005 levels – closer to, but still not in line with the 2030 pledge.
Second, despite this policy gap, Biden’s current climate policies go a significant way towards meeting the 2030 target and could be added to in the future.
Third, if Trump is able to remove all of Biden’s key climate policies, then the US is all but guaranteed to miss its targets by a wide margin.
Given the scale of US emissions and its influence on the world, this makes the election crucial to hopes of limiting warming to 1.5C. (See: The global climate implications of the US election.)
Finally, there is policy uncertainty around which policies will be finalised, how strong any final rules will be, what legal challenges they may face and how easy they prove to roll back.
There is also uncertainty – illustrated by the ranges in the chart – around the impact of Biden’s policies, the response of households, business and industry to those measures, and the rate of economic growth, as well as over future prices for fossil fuels and low-carbon technologies.
These uncertainties are partly – but not entirely – captured by the six models underlying the analysis, which have different model structures and input assumptions.
How the Biden administration is tackling warming
In 2015, the then-president Barack Obama pledged a 26-28% reduction in US emissions below 2005 levels by 2025 as an intended “nationally determined contribution” (iNDC) to the Paris Agreement.
On taking office in 2017, the climate-sceptic president Trump then pulled the US out of the Paris Agreement, attracting global opprobrium. He then rolled back or replaced Obama-era climate policies, including the Clean Power Plan, while attempting – unsuccessfully – to prop up coal.
Trump’s successor as president, Joe Biden, campaigned in 2020 on a platform of a “clean energy revolution”. On gaining office in 2021, he immediately rejoined the Paris Agreement and then issued a more ambitious pledge to cut US emissions to 50-52% below 2005 levels by 2030.
Cover photo: Alamy Stock
