This post is sponsored by Swiss Re Corporate Solutions
While the latest IPCC report, or to be precise, part one of three (with the next two detailing climate impacts and mitigation to follow shortly) makes a sobering read, it is encouraging that its important message is reaching a far broader audience beyond climate science practitioners (it just took six attempts!).
Consolidating more than 15,000 peer reviewed papers and a taskforce of more than 200 climate experts from around the world, the assessment report represents the current best view of climate science and is thus highly persuasive. However, it is important to note that our knowledge of the climate system, including all its complex feedbacks remains incomplete. As such, first time readers, and particularly those from the broader corporate community who now have a far larger vested interest in the report would benefit from an informed and critical interpretation of its findings.
Here are some of the key messages worth highlighting in my view:
Impacts of climate change are already felt TODAY
- Advances in extreme weather detection and attribution science mean that events such as wildfires, extreme rainfalls, floods and tropical cyclone activity can already be linked- to varying extents – to climate change that has already elapsed (i.e. global surface air temperature increase of +1.1 deg C increase from pre-industrial levels)
Can the report’s findings be more uncertain, yet confident at the same time?
- A rough comparison of model ensemble outputs (not the full, range but ensemble means) across IPCC reports since 1990 reveal that the most conservative (BAU) projections are getting worse, and that the range of potential futures are also widening – giving us at least theoretical hope that our mitigative actions taken today will make a significant difference in the future. The main reasons for this is improved climate science and modelling capability (i.e .higher granularity of climate model spatial resolution, improved representation of natural variability modes such as ENSO and associated feedbacks), as well as explicit socio-economic pathways (through explicit Share Socio-Economic Pathways (SSPs) and resulting emissions scenarios.
- It is interesting to note that while there is more uncertainty in the projections, there appears to be more confidence in the projections themselves evidenced by the increasing conviction used in language associated with successive IPCC reports.
Don’t be lulled into false sense of security by small changes in the mean
- This point is not new, but still important to reiterate that seemingly small changes in average temperature projections are associated with far larger changes at the tail in terms of the frequency of severe weather events. For example, although we have just warmed +1.1 deg C from preindustrial age, the recent North American heatwave has been deemed 150X more likely. As such, and because many of the climate impacts are irreversible (unlike COVID), there is an irrefutable moral and economic case to reduce additional warming as rapidly and significantly as possible.
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Check out my other piece of work around the use of catastrophe models to understand climate change Exploring Climate Change Using Cat Models