Earth Heating Faster Than Any Geological Era on Record
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- Atmospheric CO2 levels have never risen as quickly in Earth's geological record as they have over the last couple of centuries, except possibly in the immediate aftermath of the dinosaur-killing asteroid impact 66 million years ago.
- Current global temperatures are climbing at least 10 times faster than during the Palaeocene-Eocene Thermal Maximum 56 million years ago and 20 times faster than at the end of the last glacial period, according to the geological record.
- Climate models indicate that if emissions peak by 2040 and then decline rapidly, the planet would 'rewind' to a Late Pliocene climate from 3 million years ago — with temperatures 2.5°C to 4°C above pre-industrial averages, CO2 at 330 to 400 ppm, and sea levels 15 to 25 metres higher.
- Continental interiors could begin experiencing Pliocene-like conditions as early as the 2030s under that moderate-emissions scenario.
- Failure to rein in emissions could push the climate back toward the Miocene, 15 to 17 million years ago, when temperatures were 6°C to 8°C above the 1800s baseline despite CO2 concentrations of 400 to 600 ppm — a decoupling the author flags as not fully understood.
- Early Eocene hothouse conditions from 50 million years ago remain within the bounds of possibility if current heating rates continue, and the source states such conditions would render most of the world uninhabitable for humans.
- Bill McGuire, professor emeritus of geophysical and climate hazards at University College London, authored the analysis, drawn from his book published by HarperNorth.
Why it matters: Decisions made this decade will determine whether today's grandchildren inherit a Pliocene-like world (2.5-4°C hotter, 15-25m sea level rise) or something far worse — the geological record provides no precedent for heating this fast, making the next 15 years the decisive window for limiting how far back the climate clock rewinds.
