Reading the new IPCC climate crisis report: part 1

Today we’ll start our reading of the new IPCC climate report.

In this post you’ll find a summary of the “Summary for Policymakers,” along with questions, observations, and some resources. We’re following the online reading plan laid out here.

1: SUMMING UP

The Summary begins by asserting a finding: that human activities have warmed the world. The document breaks this down by parts of the world (sea, land, different atmospheric layers) and by degrees of certainty, along with room for some unevenness of cause and effect. Consequences include increased rain overall, decreased ice and snow mass, shifting some storm tracks towards the north and south poles, sea level rise, extension of growing seasons in northern hemispheric temperate regions, “climate zones have shifted poleward in both hemispheres,” and ocean acidification. How much have we heated the world? “The likely range of total human-caused global surface temperature increase from 1850–1900 to 2010–201911 is 0.8°C to 1.3°C, with a best estimate of 1.07°C.”

The main human-created sources of climate change start with carbon dioxide, followed by methane. Several sources actually reduce temperatures:

This human intervention into the climate represents a clear break from thousands of years of history: