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
And herein lies the rub – greenhouse gas levels will not suddenly stabilize.
Groundbreaking climate change agreements have been ratified, and renewable energy is on the rise from hydropowered Costa Rica to volcanically powered Indonesia. The world is beginning to try and reduce its carbon footprint, but even if every single signatory signed the Paris agreement, we may breach the 2°C (3.6°F) warming limit by 2030. Emissions will keep climbing for the foreseeable future.
Snyder worryingly estimates that, based on her detailed paleoclimate records, a doubling of the pre-Industrial levels of carbon dioxide – from 280 to 560 parts per million (ppm) – could ultimately ramp up temperatures by a whopping 9°C (16.2°F).
This disturbing value is at the high end of other study’s calculations, and some climatologists are a little skeptical of it. “I regard the study as provocative and interesting, but the quantitative findings must be viewed rather skeptically until the analysis has been thoroughly vetted by the scientific community,” Michael Mann, a paleoclimate expert at Penn State, told Climate Central.
If Snyder is correct, though, we are dangerously close to tipping over the precipice. According to the National Oceanic and Atmospheric Administration (NOAA), the global monthly average for atmospheric carbon dioxide concentrations is 401.7 ppm.
At this rate, experts think we’ll breach 560 ppm by 2100. A pandemonium of climate change disasters await.
Wildfires are becoming more potent and widespread thanks to climate change. macknimal/Shutterstock