Impacts: How hot could it get?
Image @redcharlie
“Ecosystems, species, wild populations, local varieties and breeds of domesticated plants and animals are shrinking, deteriorating or vanishing. The essential, interconnected web of life on Earth is getting smaller and increasingly frayed. This loss is a direct result of human activity and constitutes a direct threat to human well-being in all regions of the world.” – Prof. Settele, Global Assessment Report on Biodiversity and Ecosystem Services
“More frequent and intense extreme events, superimposed on long-term climate trends, have pushed sensitive species and ecosystems towards tipping points, beyond ecological and evolutionary capacity to adapt, causing abrupt and possibly irreversible changes”. – IPCC; Climate Change 2022: Impacts, Adaptation and Vulnerability
What’s the difference between 1.5°C, 2°C or a bit more? It’s just half a degree, right?
The temperatures in Figure 2 are global averages, not maximum temperatures. At the poles, average temperatures are up to 5 times this much. Just half a degree hotter is enough to trigger a cascade of dangerous tipping points, over which we have no control and cannot undo.
Think of it this way. If you add half a degree, -0.5°C of warming to ice caps and glaciers that are currently averaging -0.25°C, that would mean they are at +0.25°. That’s enough to melt across vast areas, adding to sea levels rise. Half a degree also changes the way many plants and animals behave, which brings big problems for biodiversity and agriculture, and the spread of diseases. Just a half a degree of warming increases the frequency of warm extremes over New Zealand from 93% to 234% (Fig. 3). That means even more frequent and more powerful storms, droughts, floods, and marine heatwaves.
Every fraction of a degree counts.
Carbon Brief has extracted data from around 70 peer-reviewed climate studies to show how global warming is projected to affect the world and its regions, based on 1.5°C, 2°C, and even higher warming (based on our current emissions pathway). Figures 3 and 4 are examples. Click on any image to see the full range on Carbon Brief’s website.