Zeke Hausfather
@hausfath.bsky.social
"A tireless chronicler and commentator on all things climate" -NYTimes.
Climate research lead @stripe, writer @CarbonBrief, scientist @BerkeleyEarth, IPCC/NCA5 author.
Substack: https://theclimatebrink.substack.com/
Twitter: @hausfath
Climate research lead @stripe, writer @CarbonBrief, scientist @BerkeleyEarth, IPCC/NCA5 author.
Substack: https://theclimatebrink.substack.com/
Twitter: @hausfath
It’s almost like something dramatically changed after the Industrial Revolution! (figure via Ed Hawkins)
November 18, 2025 at 4:53 PM
It’s almost like something dramatically changed after the Industrial Revolution! (figure via Ed Hawkins)
These estimates build on a broader literature of current policy estimates that I reviewed in a recent paper in Dialogues on Climate Change earlier this year: journals.sagepub.com...
November 14, 2025 at 6:52 PM
These estimates build on a broader literature of current policy estimates that I reviewed in a recent paper in Dialogues on Climate Change earlier this year: journals.sagepub.com...
A number of new estimates of current policy warming by 2100 have been released in recent months, including three prominent ones from UNEP, IEA, and CAT in the run-up to COP30.
I've got a new piece over at The Climate Brink digging into the details: www.theclimatebrink....
I've got a new piece over at The Climate Brink digging into the details: www.theclimatebrink....
November 14, 2025 at 6:52 PM
A number of new estimates of current policy warming by 2100 have been released in recent months, including three prominent ones from UNEP, IEA, and CAT in the run-up to COP30.
I've got a new piece over at The Climate Brink digging into the details: www.theclimatebrink....
I've got a new piece over at The Climate Brink digging into the details: www.theclimatebrink....
This amounts to a nearly 20% reduction in the efficacy of current global carbon sinks – that is, both the land and ocean – and a 15% reduction compared to how large they would be without the effects of climate change, leading to an increase of atmospheric CO2 of more than 8ppm since 1960.
November 13, 2025 at 3:26 AM
This amounts to a nearly 20% reduction in the efficacy of current global carbon sinks – that is, both the land and ocean – and a 15% reduction compared to how large they would be without the effects of climate change, leading to an increase of atmospheric CO2 of more than 8ppm since 1960.
The Global Carbon Budget provides estimates of both emissions and sinks (where the CO2 we emit goes). The sum of emissions should equal the sum of sinks, but because they are measured separately using different approaches they don't always completely add up:
November 13, 2025 at 3:26 AM
The Global Carbon Budget provides estimates of both emissions and sinks (where the CO2 we emit goes). The sum of emissions should equal the sum of sinks, but because they are measured separately using different approaches they don't always completely add up:
Coal, oil, gas, and cement all contributed more or less equally to the rise in emissions in 2025:
November 13, 2025 at 3:26 AM
Coal, oil, gas, and cement all contributed more or less equally to the rise in emissions in 2025:
Coal still represents the plurality of global emissions, followed by oil and natural gas:
November 13, 2025 at 3:25 AM
Coal still represents the plurality of global emissions, followed by oil and natural gas:
Chinese and EU emissions were more or less flat in 2025 (Chinese emissions may have actually declined slightly, but its too early to know for sure: www.carbonbrief.org/...).
US emissions increases drove much of the increase in global emissions in 2025.
US emissions increases drove much of the increase in global emissions in 2025.
November 13, 2025 at 3:25 AM
Chinese and EU emissions were more or less flat in 2025 (Chinese emissions may have actually declined slightly, but its too early to know for sure: www.carbonbrief.org/...).
US emissions increases drove much of the increase in global emissions in 2025.
US emissions increases drove much of the increase in global emissions in 2025.
China is the largest global emitter at 32% of global emissions, followed by the US at 13%, India at 8%, and the EU at 6%.
November 13, 2025 at 3:25 AM
China is the largest global emitter at 32% of global emissions, followed by the US at 13%, India at 8%, and the EU at 6%.
Falling fossil emissions have largely counterbalanced rising land use emissions over the past decade, leading to a plateau in global emissions. However, land use emissions remain quite uncertain, and gains made recently in reducing deforestation must be maintained.
November 13, 2025 at 3:25 AM
Falling fossil emissions have largely counterbalanced rising land use emissions over the past decade, leading to a plateau in global emissions. However, land use emissions remain quite uncertain, and gains made recently in reducing deforestation must be maintained.
The new 2025 Global Carbon Budget finds that fossil fuel emissions will reach a new high in 2025. Total CO2 emissions (including land use) remain flat at 2024 levels.
While the land sink is up from 2024, carbon sinks are weakening: www.carbonbrief.org/...
While the land sink is up from 2024, carbon sinks are weakening: www.carbonbrief.org/...
November 13, 2025 at 3:25 AM
The new 2025 Global Carbon Budget finds that fossil fuel emissions will reach a new high in 2025. Total CO2 emissions (including land use) remain flat at 2024 levels.
While the land sink is up from 2024, carbon sinks are weakening: www.carbonbrief.org/...
While the land sink is up from 2024, carbon sinks are weakening: www.carbonbrief.org/...
2.7C by 2100 under current policies, albeit with a fair bit of uncertainty.
Thankfully there is no plausible world where we get to 2.9C by 2050.
Thankfully there is no plausible world where we get to 2.9C by 2050.
November 5, 2025 at 5:47 PM
2.7C by 2100 under current policies, albeit with a fair bit of uncertainty.
Thankfully there is no plausible world where we get to 2.9C by 2050.
Thankfully there is no plausible world where we get to 2.9C by 2050.
They are my figures; here is UNEP's one with whiskers (albeit only for the values in this report).
November 4, 2025 at 8:20 PM
They are my figures; here is UNEP's one with whiskers (albeit only for the values in this report).
Hopefully under 3C (the new UNEP report gives a ~80% chance for the central estimate of current policy emissions), but big uncertainties remain.
November 4, 2025 at 6:41 PM
Hopefully under 3C (the new UNEP report gives a ~80% chance for the central estimate of current policy emissions), but big uncertainties remain.
Here is how estimates of future warming have changed over the past four UNEP reports. The estimates are down slightly from last year (largely due to methodological updates) but there isn't really a trend down in future warming estimates in recent years.
November 4, 2025 at 6:05 PM
Here is how estimates of future warming have changed over the past four UNEP reports. The estimates are down slightly from last year (largely due to methodological updates) but there isn't really a trend down in future warming estimates in recent years.
The new UNEP report is out with the latest estimates of 2100 warming outcomes under current policies, NDCs, and net-zero targets. Here is how it compares to both the IPCC scenarios and other estimates (CAT and IEA, who will release their own updates soon!).
November 4, 2025 at 6:05 PM
The new UNEP report is out with the latest estimates of 2100 warming outcomes under current policies, NDCs, and net-zero targets. Here is how it compares to both the IPCC scenarios and other estimates (CAT and IEA, who will release their own updates soon!).
Your daily dose of climate hope. From the team at RMI: rmi.org/wp-content/u...
November 3, 2025 at 11:36 PM
Your daily dose of climate hope. From the team at RMI: rmi.org/wp-content/u...
So lets take stronger action to cut SLCPs; lets just not do it in a framework that allows more CO2 emissions. Because ultimately its CO2 that is driving long-term warming of the climate system. SLCP's alone cannot credibly neutralize CO2 emissions; they need to be coupled with future carbon removal.
November 3, 2025 at 4:30 PM
So lets take stronger action to cut SLCPs; lets just not do it in a framework that allows more CO2 emissions. Because ultimately its CO2 that is driving long-term warming of the climate system. SLCP's alone cannot credibly neutralize CO2 emissions; they need to be coupled with future carbon removal.
Short-lived climate pollutants (SLCPs) have a strong near-term impact on global temps, but have a short atmospheric lifetime. They represent "flow pollutants" where the amount in the atmosphere depends on the rate of emissions, while CO2 is a "stock pollutant" that depends on cumulative emissions.
November 3, 2025 at 4:30 PM
Short-lived climate pollutants (SLCPs) have a strong near-term impact on global temps, but have a short atmospheric lifetime. They represent "flow pollutants" where the amount in the atmosphere depends on the rate of emissions, while CO2 is a "stock pollutant" that depends on cumulative emissions.
There has been a lot of recent interest in mitigating "super pollutants", short-lived climate pollutants like methane and refrigerants. We should cut emissions, but using them as carbon offsets risks breaking the math of net zero: www.theclimatebrink....
November 3, 2025 at 4:30 PM
There has been a lot of recent interest in mitigating "super pollutants", short-lived climate pollutants like methane and refrigerants. We should cut emissions, but using them as carbon offsets risks breaking the math of net zero: www.theclimatebrink....
To quote my friend @drkatemarvel.bsky.social, climate change won't make humanity extinct but we can do better than "not extinct". Raise your standards people!
October 28, 2025 at 8:46 PM
To quote my friend @drkatemarvel.bsky.social, climate change won't make humanity extinct but we can do better than "not extinct". Raise your standards people!
This continued warmth means that it is likely that 2025 will end up more or less tying 2023 as the second or third warmest year since records began in 1850.
October 28, 2025 at 3:36 PM
This continued warmth means that it is likely that 2025 will end up more or less tying 2023 as the second or third warmest year since records began in 1850.
Weather models expect global temperatures to remain relatively flat over the coming week as extreme Northern Hemisphere warmth persists, and anomalies (departures from normal) will be at or above the levels the highest levels any we've seen earlier in the year
October 28, 2025 at 3:36 PM
Weather models expect global temperatures to remain relatively flat over the coming week as extreme Northern Hemisphere warmth persists, and anomalies (departures from normal) will be at or above the levels the highest levels any we've seen earlier in the year
With 26 days of October now reporting in ERA5, October 2025 will be the third warmest on record after 2023 and 2024.
October 28, 2025 at 3:36 PM
With 26 days of October now reporting in ERA5, October 2025 will be the third warmest on record after 2023 and 2024.
After a modest decline over the first half of the year (and after record 2024 warmth), global temperatures are ticking back up. The past two days have been the warmest on record for this time of year in ERA5 and the highest temperature anomalies since January.
October 28, 2025 at 3:36 PM
After a modest decline over the first half of the year (and after record 2024 warmth), global temperatures are ticking back up. The past two days have been the warmest on record for this time of year in ERA5 and the highest temperature anomalies since January.