The world – well, everyone except Donald Trump – knows it’s getting a little hot around here. As if to add insult to injury to climate change deniers, a brand new Nature study has revealed, unsurprisingly, that Earth is now warmer than it has been in the last 120,000 years, and that it is locked into hitting its hottest mark within the next thousand years or so, no matter what happens with human activity.
A former researcher at Stanford University, and now a climate policy official at the US Environmental Protection Agency (EPA), has created a high-resolution record of the planet’s climate over the last few million years, far longer than the previous continuous 22,000-year record. Unlike many other studies that focus on year-on-year changes in recent history, this study looks back deep into the geological past, through periods of warming and cooling, and checks temperatures at 5,000-year-long intervals.
Using 61 different cutting-edge sea surface temperature measurement techniques, Dr Carolyn Snyder has come up with one of the most precise, continuous temperature records to date linking temperature changes to fluctuating carbon dioxide levels, both natural and man-made.
“It’s a useful starting place,” Snyder told Nature. “People can take this and improve upon it as more records become available in the future.”
She found clear evidence that we are living in an unusually warm period. After the last glacial maximum ended 11,500 years ago, global temperatures naturally increased, as they always do during interglacial periods. However, this study and many others clearly show how the current rate of warming is far beyond that which is expected for a post-glacial rebound.
In fact, this study goes hand-in-hand with another recent review on ocean temperatures, which dramatically highlighted that the rate of temperature increase is 10 times that which would be expected naturally. Without the oceans there to absorb so much carbon dioxide, the temperature increase rate would be 360 times the naturally expected increase.
Even with this massive carbon sink, and with all the climate mechanisms we see operating in the past continuing through to today, Snyder’s study calculates that Earth is already committed to another 5°C (9°F) of warming in the next thousand years or so if today’s current greenhouse gas levels are suddenly stabilized.
Ancient sea surface temperatures were measured using dozens of different methods. Mikhail Varentsov/Shutterstock