Michael Mann warns Earth could exceed 1.5°C warming limit

Climate scientist Michael Mann told public‑radio program Living on Earth on Tuesday that the planet is on track to breach the 1.5 °C warming limit, and that current policy trajectories will likely push global temperatures to at least 1.8 °C. The interview comes as the United Nations prepares for a high‑stakes climate summit in late September, where leaders will be urged to close the gap between pledges and the emissions cuts needed to stay below the Paris Agreement threshold.

The 1.5 °C target was set in 2015 to limit the worst impacts of climate change, such as extreme heat, sea‑level rise, and loss of biodiversity. Scientists have warned that even half a degree more can dramatically increase the frequency of deadly heatwaves, threaten food security, and accelerate glacier melt. Mann said the world’s current Nationally Determined Contributions (NDCs) fall short of the emissions reductions required to keep warming under 1.5 °C, and that without rapid policy shifts, the planet will move into a hotter, more volatile climate regime.

Mann pointed to the latest UN emissions gap report, which shows that the world is on pace for about 2.7  gigatonnes of CO₂ equivalent per year in 2030 – far above the 1.6  gigatonnes needed for a 1.5 °C pathway. He highlighted that the United States, the European Union, and China together account for roughly 60 % of global emissions, yet their current plans only lock in a 1.8 °C rise by 2100. The scientist warned that crossing 1.5 °C could trigger irreversible changes, such as the thawing of permafrost that would release additional greenhouse gases, creating a feedback loop that makes mitigation harder.

The upcoming UN summit will be a test of political will. Delegates are expected to negotiate more ambitious nationally‑determined contributions, increase climate finance for vulnerable nations, and set clearer rules for carbon markets. Mann urged leaders to act now, saying that every fraction of a degree matters and that delaying action will cost more in adaptation and economic disruption later. The summit’s outcomes could determine whether the world can still steer toward a safer climate future or lock in a hotter, riskier path.