A new paper by top climate scientists suggests that the interaction of various climate feedback loops could make it impossible to stabilize at the 2-degree Celsius target outlined in the Paris agreement, according to The Guardian. The scientists suggest that a domino effect from factors like rising temperatures, thawing permafrost, and increased methane emissions from the environment may mean that balancing the climate at Paris targets is unrealistic. Instead, the researchers investigate whether these factors could move the Earth toward 4-degree Celsius increase, resulting in an “irreversible pathway” to a “hothouse” state, even if the Paris targets are met.
Some of the natural forces that currently contribute to the planet’s resilience could ultimately feed the problem. Carbon sinks such as forests and oceans could begin contributing more carbon emissions than they can absorb.
This outcome “would almost certainly flood deltaic environments, increase the risk of damage from coastal storms, and eliminate coral reefs (and all of the benefits that they provide for societies) by the end of this century or earlier,” according to the researchers.
The paper was published in the journal Proceedings of the National Academy of Sciences on Monday, by a team that included some of the world’s leading experts on positive feedback loops. This refers to climate change processes in which rising temperatures lead to changes that increase emissions or limit the planet’s capacity to reflect heat or absorb carbon.
University of Copenhagen professor Katherine Richardson explains:
“We note that the Earth has never in its history had a quasi-stable state that is around 2C warmer than the preindustrial and suggest that there is substantial risk that the system, itself, will ‘want’ to continue warming because of all of these other processes – even if we stop emissions.”
They focus on 10 specific processes that currently help protect the planet, but could be tipped to contribute to climate change instead.
Recent studies have continued to reveal the potential damage from such feedback loops, finding these effects themselves contribute directly to rising temperatures.
The paper poses the possibility, rather than conclusively proving a theory, according to Grantham Institute Co-director, Professor Martin Siegert, who was not involved in the research.
“Threshold and tipping points have been discussed previously, but to state that 2C is a threshold we can’t pull back from is new, I think. I’m not sure what ‘evidence’ there is for this – or indeed whether there can be until we experience it,” he noted.
And another of the study’s co-authors, Johan Rockström, executive director of the Stockholm Resilience Centre, explains:
“We don’t say this will definitely happen. We just list all the disruptive events and come up with plausible occurrences.”
“We are the ones in control right now, but once we go past 2 degrees, we see that the Earth system tips over from being a friend to a foe. We totally hand over our fate to an Earth system that starts rolling out of equilibrium.”