Navigating Climate Catastrophe: Part 2 – The Response

This is Part 2 of an exploration of the current state of the climate crisis. Please read Part 1 first.

What to Expect

Because climate change is complicated and climate science is incomplete, it’s hard to predict exactly what will happen this century as a result of global warming. But we have some clues.

There’s no precedent for catastrophic climate change during human history (the most impactful climate shift for which we have documentation was perhaps the Little Ice Age of the 14th to the 19th centuries—though it was only regional, mainly affecting Europe). But, over geologic time, there is one instance that’s analogous. About 56 million years ago, natural processes produced warming that was greatly worsened by climate feedbacks. The Earth’s average surface temperature increased by 7 degrees Celsius. This event is known to geologists as the Paleocene Eocene Thermal Maximum (PETM). 

The PETM was a big deal. Triggered probably by volcanoes in the North Atlantic coinciding with a warming phase of the Milankovitch Cycle, the warming pulse was amplified by the release of methane from melting permafrost and methane hydrates. Surprisingly few creatures went extinct, but ones that survived were forced to migrate long distances. The oceans became acidic and were depleted of oxygen. Land vegetation shifted toward the poles. The warming and its immediate effects persisted for 180,000 years.

For us in the 21st century, this may represent a worst-case scenario. Good news: feedbacks that made the PETM so catastrophic haven’t kicked in yet. Bad news: the climate forcing we’re doing is of nearly as great a magnitude, and at a much greater speed.