Climate change in numbers
386 and 408.
When we launched our 10% campaign back in Autumn 2009, atmospheric C02 levels were at around 386 parts per million. When we relaunched as Possible ten years later, it was just over 408ppm.
That means that for every million bits of the atmosphere (the layers of gases which surround our Earth) over 400 of those bits are now carbon. It might not seem like much, but carbon is so good at trapping heat, it’s enough to cook up quite a problem for us humans.
We’ve known that an atmosphere heavy with carbon could cause global warming since the 1850s when Eunice Foote and John Tyndall ran some of the first climate science experiments.
Since the 1950s, we’ve been worried enough to keep track of how much carbon is in the atmosphere. There’s a lab in Hawaii that has been measuring atmospheric CO2 since 1958. This is how we know it’s going up, and where we got the numbers 386 and 408 from. If you were born after 1958, and want to look up your birthday, the data is all on their site. You can even follow them on Twitter.
1.5 and 2.
Back in 2015, the Paris US climate talks made history when they agreed to look again at the possibility of keeping global warming to 1.5 degrees Celsius. Previously, a lot of the talk at the UN level had been about keeping to 2C.
They commissioned the Intergovernmental Panel on Climate Change (the IPCC) to report on whether keeping to 1.5C was possible, and what would need to happen. This report was published in October 2018, and made quite stark reading: we can keep to 1.5C, but it’ll be hard.
Half a degree might seem a small amount, but we’re not talking about the differences in temperature from one bit of the office to the other. These are average global temperatures for the whole world, year on year. And for these, every fraction of a degree matters.
There are significant differences when it comes to how many millions of people will be exposed to extreme weather. At 1.5C, 14% of the world’s population would face a severe heatwave at least every five years and 50% every 20 years. At 2C, this rises to 27% and 70% respectively. The difference between 1.5C and 2 is also the difference between an ice-free summer in the Arctic every 100 years and one at least every ten. It’s the difference between keeping about 70% of our coral reefs and having none at all, and insects and plants are almost twice as likely to lose half their habitat at 2C compared to 1.5C.
A 1.5C world is no picnic. We’re already creeping towards 1C and it’s already hurting. 2 degrees was never safe and we shouldn’t have left it so long to seriously look to 1.5C. Still, climate change isn’t a pass or fail issue; there’s still so much more to fight for.