Over the last decade the world has cut projected emissions by more than 40 percent.

The claim is that over roughly the last decade (about 2015 to 2025), projected global emissions (future emissions expected under current policies, compared with earlier projections) have fallen by more than 40%. True: credible analyses (for example IEA, Climate Action Tracker, UNEP Emissions Gap reports or the source Gates cites) show current-policy emissions projections for a target year (such as 2040 or 2100) are more than 40% below the projections made about a decade earlier. Mostly true: the reduction is somewhat below 40% (about 35% to 40%), or holds only for one particular baseline or target year. Mixed: sources disagree widely, with some showing more than 40% and others well below it. Mostly false: projected emissions fell, but by clearly less than 35%, or the figure rests on an unrepresentative comparison. False: projections have not fallen meaningfully.

Set before the research began.

1. E1 Fact Check: Have projected 2040 carbon dioxide emissions been revised downward by 40% in the past decade? | Econofact Econofact · 17 November 2025

   “The 2024 International Energy Agency forecast for yearly global CO2 emissions in 2040 was 31 gigatonnes, 18% lower than the 38 Gt predicted in 2014.”

2. E2 Current Policies Scenario – World Energy Outlook 2025 International Energy Agency · 12 August 2026

   “Annual global energy-related CO2 emissions rise slightly from current levels and approach 40 gigatonnes of carbon dioxide per year in the early 2030s, remaining around this level through to 2050.”

3. E3 The Year Ahead 2026: Optimism with Footnotes | Bill Gates Gates Notes (Bill Gates) · 9 January 2026 Own record

   “Ten years ago, the International Energy Agency predicted that by 2040, the world would be emitting 50 billion tons of carbon dioxide every year. Now, just a decade later, the IEA’s forecast has dropped to 30 billion, and it’s projecting that 2050 emissions will be even lower.”

4. E4 World Energy Outlook 2017 – Analysis - IEA International Energy Agency · 16 November 2017

   “Projected 2040 emissions in the New Policies Scenario are lower by 600 million tonnes than in last year’s Outlook (35.7 gigatonnes [Gt] versus 36.3 Gt).”

Gates's claim rests on his own statement that the IEA's 2040 forecast fell from 50 to 30 billion tons (E3). He attributes the 50-billion figure to the IEA, but the quoted passage does not name the IEA report it comes from, and that report is not among the evidence. An independent fact check found that the IEA's 2040 CO2 forecast fell from 38 Gt (made in 2014) to 31 Gt (made in 2024), a drop of 18% (E1). The IEA's 2025 Current Policies Scenario projects emissions near 40 Gt per year through 2050 (E2), and the IEA revised its 2040 projection down by 0.6 Gt between the 2016 and 2017 Outlooks (E4: 36.3 to 35.7 Gt). Projected emissions did fall, but the independent comparison available (E1) shows a drop of 18%, clearly below 35%, so the claim resolves mostly false.