The Intergovernmental Panel on Climate Change (IPCC) is due to issue a Special Report the spells out the impact Global Warming of 1.5 °C or above. It will be formally issued next October, but there is a public draft already available for comment, hence we can get a look to see what it will tell us.
Warning: this is a working draft, the authors will process comments and also as new research become available modify it.
If you do in fact follow climate change related news then the content will be neither a surprise nor a shock.
The availability of the draft is referred to by some as a “leak”. That is perhaps a bit of hype. I’m personally not convinced that a publicly available working draft that is available for anybody to comment upon is a “leak”. The IPCC are very transparent about their process and that includes work in progress.
What does the draft tell us?
Because it is a working draft that is still subject to change, I’ll not cite it directly, but will instead give you an idea of what it tells us. The essence of some of it is this …
- There is a very high risk that Global warming will exceed 1.5 C (we are already at 1 C)
- Even if we did suddenly eliminate rather of lot of CO2 emissions, and so managed to constrain global warming to just 1.5 C, we still face extreme events over both oceans and also land. One example of this is the observation that at 2 C or even 1.5 C sea level will continue to rise each and every year for centuries.
- They make the observation that we will reach 1.5 C of warming by the 2040s. The basis for this is the observation that the warming trend globally sees an increase of 0.17 C per decade.
- Delaying meaningful action now will make it a lot harder to address further down the road.
- Avoiding substantial warming is possible
- It would require rapid and deep reductions in greenhouse gas emissions
- Impacts of 1.5 C
- Some impacts are irreversible, for example the mortality of species or ecosystems, hence even brief periods of overshooting the 1.5 C limit can lead to such impacts.
- Distilling it all … heatwaves, more intense storms and more frequent storms, floods, droughts. There is also a greater risk in the Arctic because the warming there is greater than the average.
- Global warming in the oceans will change the basic chemistry of the oceans – acidification will impact biological ecosystems. Fisheries and aquaculture will be impacted.
It’s a working draft
As previously mentioned, this is a work in progress.
The IPCC has issue specific warnings for media outlets to not cite the draft because it is a working document that is subject to change …
– Firstly, the text can change substantially between the Second Order Draft and the final version once the report’s authors have carefully considered every individual government and expert review comment. For instance, the First Order Draft of this report received 12,895 comments from nearly 500 expert reviewers. Like any work in progress, it is important to respect the authors and give them the time and space to finish writing before making the work public.
– Secondly, the Second Order Draft is based on scientific literature published or submitted for publication before 1 November 2017. Newly published scientific evidence highlighted by reviewers can still be taken into account between the Second Order Draft and the final version of the report, as long as it is accepted for publication in a journal before 15 May 2018.
It is indeed just that – a draft – and so be aware that the final version which will address the literally thousands of comments, including those from subject matter experts, will be different.
Despite that point, what it does give us is a rather clear indication regarding which way the wind is currently blowing. While it might indeed be just a draft, this is an early expression of the evidence-based thinking within the climate community.