CLIMATE CHANGE AND PLANET HEATWAVE Letter to the Times 29 July

[Reg Hand]

CLIMATE CHANGE AND PLANET HEATWAVE
Sir, Tom Whipple (“No need to panic about our heatwave planet”, Comment, July 27) draws comfort on climate change from the geological record. He is right to do so, provided that we hit the targets set at the 2015 Paris climate summit. If we go beyond those Paris limits, however, we risk triggering events with which we cannot cope.

There are two major natural controls on the Earth’s climate. One control is periodic, a geological clock controlled by variations in our planet’s orbit around the Sun. These variations are beyond our control: climate stability is not an option.

The second major control is episodic, as in geologically sudden release of large volumes of carbon into the atmosphere. Examples are carbon-triggered warming events 183 and 56 million years ago.

If we pull our own episodic carbon trigger beyond the Paris safety catch, we risk causing even larger natural releases on top of our own. We need to be especially wary, because we are releasing carbon ourselves many times more rapidly than happened naturally in the Jurassic and Paleocene events.

We must go beyond the inadequate national commitments made at Paris on the release of carbon. A crucial recent development is the Task Force on Climate-Related Financial Disclosures, led by Michael Bloomberg. This task force was set up in December 2015 by the G20’s financial stability board, chaired by Mark Carney. Multinational corporations are taking the lead on climate change through this task force while nations hesitate.
Bryan Lovell
Senior research fellow in Earth sciences, University of Cambridge