Transition énergétique ?

Research in Chile suggests climate crisis makes eruptions more likely and explosive, and warns of Antarctica risk

The world has been too optimistic about the risk to humanity and planet – but devastation can still be avoided, says Timothy Lenton

Ten kinds of possible collapses examined.

Tipping elements within the Earth system are increasingly well understood. Scientists have identified more than 25 parts of the Earth’s climate system that are likely to have “tipping points” – thresholds where a small additional change in global warming will cause them to irreversibly shift into a new state. The “tipping” of these systems – which include the Atlantic Meridional Overturning Circulation (AMOC), the Amazon rainforest and the Greenland ice sheet – would have profound consequences for both the biosphere and people. More recent research suggests that triggering one tipping element could cause subsequent changes in other tipping elements, potentially leading to a “tipping cascade”. For example, a collapsed AMOC could lead to dieback of the Amazon rainforest and hasten the melt of the Greenland ice sheet.

Lenton, the founding director of the Global Systems Institute at the University of Exeter, was the lead author of the 2008 paper that formally introduced the idea of tipping points in the Earth’s climate system.

The ocean ecosystem is a vital component of the global carbon cycle, storing enough carbon to keep atmospheric CO2 considerably lower than it would otherwise be. However, this conception is based on simple models, neglecting the coupled land-ocean feedback. Using an interactive Earth system model, we show that the role ocean biology plays in controlling atmospheric CO2 is more complex than previously thought. Atmospheric CO2 in a new equilibrium state after the biological pump is shut down increases by more than 50% (163 ppm), lower than expected as approximately half the carbon lost from the ocean is adsorbed by the land. The abiotic ocean is less capable of taking up anthropogenic carbon due to the warmer climate, an absent biological surface pCO2 deficit and a higher Revelle factor. Prioritizing research on and preserving marine ecosystem functioning would be crucial to mitigate climate change and the risks associated with it.

Antarctica's remote and mysterious current has a profound influence on the climate, food systems and Antarctic ecosystems. Can we stop it weakening by 2050?

A panel of international scientists has moved their symbolic “Doomsday Clock” closer to midnight than ever before, citing Russian nuclear threats amid its invasion of Ukraine, tensions in other world hotspots, military applications of artificial intelligence and the climate crisis as factors underlying the risks of global catastrophe.

A new report explores a framework for global climate risk management and includes contributions from an actuary at the Government Actuary's Department.

A new report from U.K. actuaries and climate scientists "shows a 50% GDP contraction between 2070 and 2090 unless an alternative course is chartered," said the lead author.​