Bi-monthly thread on climate solutions and responses.
Unforced variations: Aug 2019
Unforced variations: July 2019
Absence and Evidence
Guest commentary by Michael Tobis, a retired climate scientist. He is a software developer and science writer living in Ottawa, Ontario.
A recent opinion piece by economist Ross McKitrick in the Financial Post, which attracted considerable attention in Canada, carried the provocative headline “This scientist proved climate change isn’t causing extreme weather – so politicians attacked”.
In fact, the scientist referenced in the headline, Roger Pielke Jr., proved no such thing. He examined some data, but he did not find compelling evidence regarding whether or not human influence is causing or influencing extreme events.
Should such a commonplace failure be broadly promoted as a decisive result that merits public interest?
[Read more…] about Absence and EvidenceUnforced Variations vs Forced Responses?
Guest commentary by Karsten Haustein, U. Oxford, and Peter Jacobs (George Mason University).
One of the perennial issues in climate research is how big a role internal climate variability plays on decadal to longer timescales. A large role would increase the uncertainty on the attribution of recent trends to human causes, while a small role would tighten that attribution. There have been a number of attempts to quantify this over the years, and we have just published a new study (Haustein et al, 2019) in the Journal of Climate addressing this question.
Using a simplified climate model, we find that we can reproduce temperature observations since 1850 and proxy-data since 1500 with high accuracy. Our results suggest that multidecadal ocean oscillations are only a minor contributing factor in the global mean surface temperature evolution (GMST) over that time. The basic results were covered in excellent articles in CarbonBrief and Science Magazine, but this post will try and go a little deeper into what we found.
[Read more…] about Unforced Variations vs Forced Responses?References
- K. Haustein, F.E.L. Otto, V. Venema, P. Jacobs, K. Cowtan, Z. Hausfather, R.G. Way, B. White, A. Subramanian, and A.P. Schurer, "A Limited Role for Unforced Internal Variability in Twentieth-Century Warming", Journal of Climate, vol. 32, pp. 4893-4917, 2019. http://dx.doi.org/10.1175/JCLI-D-18-0555.1
Unforced Variations: June 2019
This month’s open thread for climate science discussions. Remember discussion about climate solutions can be found here.
Forced responses: May 2019
A bimonthly open thread on climate solutions and policies. If you want to discuss climate science, please use the Unforced Variations thread instead.
Unforced variations: May 2019
This month’s open thread about climate science topics. For discussions about solutions and policy, please use the Forced Responses open thread.
Unforced variations: April 2019
This month’s open thread on climate science issues. Remember that discussions about climate solutions go here.
Alpine glaciers: Another decade of loss
Guest Commentary by Mauri Pelto (Nichols College)
Preliminary data reported from the reference glaciers of the World Glacier Monitoring Service (WGMS) in 2018 from Argentina, Austria, China, France, Italy, Kazakhstan, Kyrgyzstan, Nepal, Norway, Russia, Sweden, Switzerland and United States indicate that 2018 will be the 30th consecutive year of significant negative annual balance (> -200mm); with a mean balance of -1247 mm for the 25 reporting reference glaciers, with only one glacier reporting a positive mass balance (WGMS, 2018).
