Take stock of our past, present and future climate

Before you say anything, I know it’s actually almost April. But this week has the distinct feeling of a sort of New Year’s weather change for me. Not only is it the spring equinox this week, which is celebrated like the new year in some cultures (Happy Nowruz!), but we also saw a big UN climate report drop on Monday, which puts me in a very contemplative mood.

The report comes from the Intergovernmental Panel on Climate Change (IPCC), a group of scientists who publish reports on the state of research on climate change.

The IPCC works in cycles of seven years, more or less. Each cycle, the group reviews all the published literature on climate change and brings together a handful of reports on different topics, leading to a summary report that sums it all up. This week’s release was one such summary report. It follows one from 2014, and we should see another one around 2030.

Because these reports are a sort of synthesis of existing research,I thought of this moment as a time of reflection. So for this week’s newsletter I thought we could get into the spirit of the new year and take a look at where we came from, where we are and where we’re going on change climatic.

Past climate: 2014

Let’s start in 2014. The concentration of carbon dioxide in the atmosphere was just under 400 parts per million. Pharrell Williams’ song “Happy” was slowly driving me crazy. And in November, the IPCC published its fifth summary report.

Parts of the 2014 IPCC Synthesis Report sound familiar. Its authors made it clear that human activity is causing climate change, that adaptation will not reduce it, and that the world must take action to limit greenhouse gas emissions. I saw all those same lines in this year’s report.

But there are also striking differences.

First, we were in a different place politically. World leaders had yet to sign the Paris Agreement, the landmark treaty that set the goal of limiting global warming to 2°C (3.6°F) above pre-industrial levels, with a target of 1.5°C (2.7°F). The 2014 evaluation report laid the foundation for this agreement.