Positive feedback loops could lead to a hothouse Earth

A new scientific report warns that even modest future CO2 emissions could set off a cascade of positive feedback loops that would push the planet into a hothouse state. As set out in the Paris Agreement, average global temperatures are just over 1⁰C above pre-industrial levels with actions to keep global warming limited to 2⁰C by the end of the century. There is now concern of whether the earth’s temperature can stabilise at 2⁰C above pre-industrial levels or whether it will gravitate towards a more extreme state which is far less supportive of human life.

Although their analysis is not conclusive, scientists feel that there is a substantial risk that even with halted emissions, the earth will continue to warm due to positive feedback loops. In these loops, new sources of greenhouse gases are released by warming temperatures which also destroy the Earth’s ability to reflect heat or store carbon. New feedback loops are still being discovered but there are huge gaps in knowledge and data about how various factors may amplify another and interact at a global level. For example, the loss of Greenland’s ice could cause disruption to the Gulf Stream which in turn would raise sea levels and the temperature of the Southern Ocean. This would result in accelerated ice loss from the east Antarctic.

“In the context of the summer of 2018, this is definitely not a case of crying wolf, raising a false alarm: the wolves are now in sight,”- warned Dr Phil Williamson, Climate Researcher at the University of East Anglia.

While the diagnosis of climate change is a global scientific issue, the response to it is not. Investing in renewable energy and modernising the housing stock to be energy efficient is a question of policy choice and overcoming the lobbying power of the building industry. Therefore, in addition to reducing greenhouse gas emissions as fast as possible, a more proactive approach is needed in talking about climate change and engaging in politics at all levels. Nevertheless, the summer heatwaves of 2018 have been a reminder that impending shifts in climate will not be smooth or gradual.


Source: https://www.theguardian.com/environment/2018/aug/06/domino-effect-of-climate-events-could-push-earth-into-a-hothouse-state

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