Taking stock of our climate past, present, and future

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

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

The IPCC works in seven-year cycles, give or take. Each cycle, the group looks at all the published literature on climate change and puts together a handful of reports on different topics, leading up to a synthesis report that sums it all up. This week’s release was one of those synthesis reports. It follows one from 2014, and we should see another one around 2030. 

Because these reports are a sort of summary of existing research, I’ve been thinking about this moment as a time to reflect. So for the newsletter this week, I thought we could get in the new year’s spirit and take a look at where we’ve come from, where we are, and where we’re going on climate change. 

Climate past: 2014

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

Some bits of the 2014 IPCC synthesis report feel familiar. Its authors clearly laid out the case that human activity was causing climate change, adaptation wasn’t going to cut it, and the world would need to 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 hadn’t yet signed the Paris agreement, the landmark treaty that set a goal to limit global warming to 2 °C (3.6 °F) above preindustrial levels, with a target of 1.5 °C (2.7 °F). The 2014 assessment report laid the groundwork for that agreement.