Atmospheric CO2 hit a seasonal record in May, and Climate Central warns average global temperatures this summer could briefly reach about 3.5°F above pre-industrial levels. Scientists say this spike highlights how human emissions are intensifying lethal heat waves, storms, and wildfire risk. Non-government groups (Climate Central, Berkeley Earth, Copernicus) are stepping in to provide public briefings and translate data into tangible risks for health, homes, and economies. Researchers stress that cutting fossil fuels and accelerating clean energy are essential to slow these trends.
Record May CO2 Could Push This Summer About 3.5°F Above Pre‑Industrial, Raising Heat, Storm and Fire Risks
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Climate scientists warn that a record rise in atmospheric carbon dioxide in May could briefly push average global temperatures this summer to about 3.5°F (≈1.9°C) above pre-industrial levels, underscoring how human emissions are accelerating dangerous climate impacts.
Atmospheric scientist Zack Labe opened Climate Central's monthly briefing by noting that CO2 typically peaks each May; this year, NASA data show that the seasonal maximum reached a new high. Labe added that warming caused by human activity is expected to intensify deadly heat waves, strengthen storms, and increase wildfire risk.
Climate Central's monthly summaries are serving as a substitute for the National Oceanic and Atmospheric Administration's briefings, which were canceled last year following budget cuts under the Trump administration. Several contributors to the Climate Central briefing, including meteorologist Tom Di Liberto, previously worked at NOAA and say there is public demand for expert explanation of the data.
"We heard from a lot of folks that they missed the NOAA briefings and being able to talk with experts," Di Liberto said. "We were happy to tap into Climate Central's expertise and combine it with our NOAA experience to bring this to fruition."
Other Scientific Warnings
The record CO2 signal comes amid broader warnings: former NASA scientist James Hansen has said 2026 could be the hottest year on record, while the European Union's Copernicus climate service reports that Earth is accumulating heat faster than at any other time in the observational record. Researchers point to the planet's growing "energy imbalance"—more incoming and retained energy than is leaving space—as a clear measure of the pace of climate change.
Samantha Burgess, Copernicus' strategic lead for climate, said: "Nearly all of the warming over the last decade is driven by human activities."
University of Leeds climate scientist Piers Forster added that the energy imbalance "provides a crucial measure of the pace of climate change."
Impacts On People And Communities
Higher average temperatures and a stronger energy imbalance increase the likelihood and severity of extreme weather. Severe heat causes heat stroke, worsens heart and lung conditions, and makes outdoor work hazardous. Stronger storms, floods, and wildfires destroy homes, disrupt businesses, harm crops, raise insurance costs, and force evacuations.
Non-government organizations such as Climate Central, Berkeley Earth, and Copernicus are increasingly filling the public-briefing role by publishing regular analyses from global monitoring networks, helping maintain public access to climate data amid reductions in some government updates.
What Scientists Say Should Be Done
Researchers emphasize that the pathway to slowing these trends remains the same: cut fossil fuel emissions, accelerate deployment of clean energy, and strengthen resilience to heat, storms, and fires. Without those actions, seasonal records and their associated harms are likely to become more frequent and more severe.
Bottom line: The new May CO2 record is another clear sign that human-driven emissions are pushing the climate system toward higher temperatures and greater risks—making rapid emissions reductions and adaptation measures urgent priorities.
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