Global warming could be double What models predict

Global warming could be much worse than current climate models.

Researchers often use records from the Earth's past to predict changes in the future. A final assessment of past warm periods shows that future global warming could be twice as warm as predicted by climate models and that sea level could rise six meters or more with 2 ° C warming.

A world warming towards 2C is considered the limit of a climate-friendly planet and the 2015 Paris climate agreement aims to keep global warming well below average 2 ° C by reducing carbon emissions. "Observations from past warm-ups suggest that a number of amplifying mechanisms, poorly represented in climate models, increase long-term warming beyond the projections of the climate model," explains Professor Hubertus Fischer of University of Bern. avoiding 2 ° C of global warming could be much lower than estimated, leaving very little room for error to achieve the Paris targets. "

To make predictions, the researchers examined three past warm periods, the Holocene thermal maximum. (9000 years ago), the last interglacial period (129,000 to 116,000 years ago) and the warm Middle Pliocene period (3.3 to 3 million years ago.)

The warming of the first two periods was linked to predictable changes in the Earth's orbit, while the third period was There has been an increase in atmospheric concentrations of carbon dioxide Carbon dioxide is also the main driver of climate change today

When researchers combined a wide range of measurements from ice cores, sediments , fossils and other techniques, they have been able to better predict future climate reactions.The result suggests that our planet today is warming much faster than any of these p Even if we limit carbon emissions, it would take centuries or millennia to reach equilibrium. "Even with only 2 ° C of warming – and potentially only 1.5 ° C – the significant impacts on the Earth's system are deep" Professor Alan Mix of Oregon State University

"We can expect to that the rise in sea level becomes irreversible for millennia, affecting a large part of the world's population, infrastructure and economic activity. "