Robert Rohde
Chief Scientist for @berkeleyearth.org.
Physics PhD & data nerd. Usually focused on climate change, fossil fuels, & air quality issues.
- Reposted by Robert RohdeNew discussion paper just dropped that’s taken shall we say a little work to get this far … essd.copernicus.org/preprints/es... please be kind. Not on an at all sensitive topic in the slightest.
- It is wild to me that in 2025 the question of how much does solar output change during a solar cycle still comes with a ~20% measurement uncertainty.
- I understand why it is hard. Total solar irradiance is ~1361 W/m², so measuring a ~1 W/m² change is less than a 0.1% change. And it can only be done with satellites, which often degrade and get replaced, requiring the synthesis of many (sometimes inconsistent) measurements.
- Now, forcings due to additional greenhouse gases are clearly larger than the observed solar changes. But total solar irradiance remains a pretty important boundary condition for all climate and climate change work. One would think that we would have solar variation nailed down better by now.
- Reposted by Robert RohdeWe're one year in. The speed, scope and severity of what's happening to American science is beyond anything we've seen before. The reliability of the Federal science and technology enterprise and the people within it, has been shattered. www.nature.com/articles/d41...
- For 50 years, global warming had a very consistent trend (+0.19 °C/decade) with a boring, predictable range of natural variations around it. During the last three years, we've broken out above that range, suggesting the pace of change has quickened.
- Nearly linear warming over recent decades is in line with what models expect based on the observed history of greenhouse gases that have been added to the atmosphere. But the warming experienced in 2023, 2024, and 2025 suggest additional factor(s) are having an effect.
- For further discussion, see yesterday's thread and @berkeleyearth.org's Annual Report. bsky.app/profile/did:...
- While the world sometimes seems metaphorically on fire right now, global warming is still progressing as well. In 2025, global warming delivered the 3rd warmest year since measurements began. A modest step down from 2024's records, but still well above 20th century norms. 🧪🧵
- The warming spike of the last three years is a small but significant deviation above the long-term warming trend of the prior 50 years. At least in this short-term, recent global temperatures have risen faster than expected.
- Humans have been adding greenhouse gases to the atmosphere. These changes are easily measurable. Over the last fifty years, the expected amount of warming due to the observed increase in greenhouse gases (mostly from carbon dioxide) has remained nearly linear.
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View full threadFor more background on 2025 temperatures from a climate context, please see @berkeleyearth.org's annual report: berkeleyearth.org/global-tempe...
- The US Government is literally saying that human lives have no value.
- Under President Trump, the EPA will stop considering lives saved when setting pollution limits and instead calculate only the cost to businesses. It’s counter to the agency’s mission statement, which says has a core responsibility to protect human health and the environment. nyti.ms/3Loch27
- Reposted by Robert Rohde📊 Berkeley Earth 2025 Annual Temp Report Release: Jan 14 4am CET | Jan 13 10pm ET | 7pm PT Embargoed Materials: Jan 13 (TBD) Media Sign up: tinyurl.com/mrxuy5a2 Press briefing + Q&A will follow at 8am PST | 5pm CET on Jan 14. Register: tinyurl.com/2hj6j8t3 Inquiries: 📩 media@berkeleyearth.org
- The USA has become the only UN member state to turn their back on the UNFCCC foundational climate change treaty and @ipcc.bsky.social. This is a giant FU to international climate change research & action from the world's leading producer of oil and gas producer. www.whitehouse.gov/presidential...
- You know a great way to drive up energy costs? Have the government block energy projects that have already been under construction for years, forcing companies to take billion dollar losses while delivering no energy at all.
- There will be litigation, but realistically this could well mark the end of any new offshore wind projects in the USA until Trump leaves office. Multiple gigawatts of wind power at sites already under construction are likely to be abandoned. www.cnn.com/2025/12/22/c...
- There will be litigation, but realistically this could well mark the end of any new offshore wind projects in the USA until Trump leaves office. Multiple gigawatts of wind power at sites already under construction are likely to be abandoned. www.cnn.com/2025/12/22/c...
- Reposted by Robert RohdeNOAA has started terminating grants to UCAR under the UCAR/NOAA Climate Adaptation and Mitigation Program (CAMP).
- Reposted by Robert RohdeA massive new report by over 100 scientists modeling the climate effects of the 2022 Hunga volcanic eruption finds "The record-high global surface temperatures in 2023/2024 were not due to the Hunga eruption": juser.fz-juelich.de/...
- The big special report on the Hunga Tonga eruption is out: juser.fz-juelich.de/record/10491... After a couple years of arguing whether the net effect of aerosols+water vapor was warming or cooling, it includes this banger of a model ensemble that literally does cooling then warming.
- That's not an entirely insane outcome. Stratospheric aerosols and water vapor evolve in different ways, with the warming water vapor persisting longer than the cooling aerosols. Even so, the model suggestion of a meaningful sign flip is a bit wild.
- Also, one should be aware of those large error bars, and though this is a 30-member ensemble, it is still just one weather model. Probably not the last word, but likely the best model guidance we have right now. A small-to-moderate effect with a complicated time evolution.
- Reposted by Robert RohdeI know many of you who follow me don't work in climate science, but this is the biggest story in climate right now. Breaking up NCAR makes us all less safe and is another act of self-harm that will take decades to recover from.
- The cost of grid-scale solar plus batteries has become so cheap that spreading solar power out over 24 hours is now cost-competive with building new natural gas plants in many cases. ember-energy.org/latest-insig...
- Shifting solar from day-only to a full 24 hours isn't a complete solution. You still have to worry about weather and seasonality. But it makes solar power much more flexible and easier to integrate into the grid.
- The EU enacted legislation to ban internal combustion engines in all new car sales starting in 2035. Reportedly, this will get watered down. The total ban would be replaced with fleet-wide new car limits requiring a 90% reduction in carbon emissions. www.euractiv.com/news/von-der...
- Reposted by Robert RohdeJay Bhattacharya and Matthew Memoli aren't bringing "gold standard science" to the #NIH, they are gutting research slowly but surely. When this time is over, they should be hauled before Congress, and shunned for the rest of their lives. www.nytimes.com/interactive/...
- Recently, @berkeleyearth.org expanded our temperature database by integrating the HCLIM data set. nature.com/articles/s41... The additional data rescued by HCLIM helps improve early reconstructions, but doesn't fundamentally change the large uncertainties due to sparse sampling. 1/
- Though accurate liquid-in-glass thermometers were invented in early 18th century, weather monitoring remained sparse for the next ~150 years. 2/
- In very early instrumental reconstructions (pre-1850), one is often only sampling a small area, e.g. ~15% of the Earth. Using modern weather patterns, one them estimates how different the other ~85% is likely to be from the part you can see, giving rise to an uncertainty. 3/
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View full threadOften early weather data exists only on paper records in some obscure government or university storage facility. Finding them and digitizing them for further use helps to open up new insights and data that would not be available in other ways. 6/6
