Average Global Temperature Change?
From today’s conversations about climate change one could be forgiven for thinking that the main question we have to answer is whether to focus on limiting average global temperature rise to 1.5o C or to 2o C?
There is no reason to assume, however, that average global temperature change will be limited to 2o C, much less the more aggressive target of 1.5o C. Assuming that one of these targets will be achieved “because it must be,” as is common in both societal and business climate risk discussions today, reflects a "false certainty." The plausible range of potential climate change outcomes is actually much larger:
- >5o C is not out of the question given the known unknowns of the climate system and the possibility of unknown unknowns.
- 3-5o C represents today’s most likely climate outcome by 2100, based on “stay the current course” climate policies and measures. 3.5o C has also been characterized as a “best case” given the fact that no matter how hard we try, the response to climate change will not reflect the results of optimization studies.
- 2o C scenario is today’s prevalent climate change public target, but one that may or may not be achievable.
- 1.5o C roughly represents the idea of returning CO2 concentrations in the atmosphere to 350 ppm; it is being called for by scientists and activists around the world, but is probably outside the realm of possibility.
In reality, the 1.5o C target is already pretty much off the table, and the 2o C target is rapidly headed for the same outcome.
Because the topic of “how high will temperatures go?” is important to almost all aspects of risk assessment and management around climate change, we’ll dig into it quite a bit.
Questions you can explore in the Climate Web
- Is there a “safe” level of average global temperature rise?
- Why seemingly modest global temperature changes create so much business uncertainty?
- Is average global temperature, which is based on a long-term rolling average, the best way to communicate climate risk?
- What’s the most likely 2100 temperature forecast, taking into account that the global response will never be optimized?
- How much could average global temperature rise by 2050, 2100, and beyond?
- What’s the likelihood of limiting average global temperature change to 1.5o or 2o C? (What would be required is covered in a later module)
- What would be some of the key implications of alternative levels of average global temperature rise?
- How Climate Stripes are helping with visualizing temperature change?
Insights Pages
- Is There a Safe Level of Climate Change?
- How Much Climate Change is Likely? In Process
- How Much Change is Possible?
- George Backus on Why 3.5o C May be the Best We Can Do
- What Happens to Global Temperature After 2100?
- .10 Climate Stripes
- Local vs. Global Temperatures