EESC Lecture 10 - Climate Model Scenarios

Climate Change Model Scenarios - What are they, what are their underlying assumptions, how well do they perform, and how are they best applied? These are the topics I explore in this lecture.
In the spirit of Nullias in verba (take the word of nobody), this lecture was presented as an assignment for students to fact check my material. This topic has been a passion of mine since teaching an introductory course a few years ago, as I discuss in the introduction.
Incidentally, this is the last UBC lecture I’ll be posting, at least for awhile. I’ve decided to step away from teaching to spend the next few years travelling - there are so many pit lakes to visit!
Here are my references, in case you would like to do your own fact checking:
Burgess, M. G., Ritchie, J., Shapland, J., & Pielke, R. (2020). IPCC baseline scenarios have over-projected CO2 emissions and economic growth. Environmental Research Letters, 16(1), 014016.
Fyfe, J. C., Gillett, N. P., & Zwiers, F. W. (2013). Overestimated global warming over the past 20 years. Nature Climate Change, 3(9), 767-769.
Hausfather, Z., & Peters, G. P. (2020). Emissions - the ‘business as usual’ story is misleading. Nature, 577(7792), 618-620. doi.org/10.103...
IPCC. (2013). Evaluation of Climate Models (Section 9; Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the IPCC, p. 126). Intergovernmental Panel on Climate Change Working Group 1.
IPCC. (2014). Near Term Climate Change: Projections and Predictability. IPCC Assessment Report 5 Working Group1 Volume 11 (WG1 AR5 11; p. 76). United Nations Intergovernmental Panel on Climate Change.
Koonin, S. E. (2021). Unsettled: What Climate Science Tells Us, What It Doesn’t, and Why It Matters. BenBella Books.
NSIDC. (2022). National Snow and Ice Data Center |. nsidc.org/
Palmer, T., & Stevens, B. (2019). The scientific challenge of understanding and estimating climate change. Proceedings of the National Academy of Sciences, 116(49), 24390-24395. doi.org/10.107...
Papalexiou, S. M., Rajulapati, C. R., Clark, M. P., & Lehner, F. (2020). Robustness of CMIP6 Historical Global Mean Temperature Simulations: Trends, Long‐Term Persistence, Autocorrelation, and Distributional Shape. Earth’s Future, 8(10). doi.org/10.102...
Pielke, R., & Ritchie, J. (2021). Distorting the view of our climate future: The misuse and abuse of climate pathways and scenarios. Energy Research & Social Science, 72, 101890. doi.org/10.101...
Pielke Jr R, Burgess MG, Ritchie J (2022) Plausible 2005-2050 emissions scenarios project between 2°C and 3°C of warming by 2100. Environ Res Lett 17:024027. doi.org/10.108... 9326/ac4ebf
Ritchie, J., & Dowlatabadi, H. (2017). Why do climate change scenarios return to coal? Energy, 140, 1276-1291.

[@Aikidoman06]

I’m an engineer and this is a simple process: you take all known climate data up to last month and run the simulation to see if it produces that same data as the current months weather data. The problem is the climate models have been wildly wrong, and the further out they project the more wrong they become. The other problem with their approach is that it’s all geared towards proving its changing, and no looking at it being cyclical fluctuations

[@matthewalan59]

I am an engineer as well. However, I understand the difference between weather climate. No one who understands this distinction would make the claim, as you seem to have done, that any climate model would predict the current months weather. Also, it is not a simple process. Also, the general trends predicted by various climate models have been wildly accurate.

[@Aikidoman06]

@@matthewalan59 my claim was over simplified. As an engineer you understand anything you test is complicated by each additional variable. Taking the current climate models and considering the innumerable number of veritable sits impossible to build a working model. It’s clearly not my field, but using a climate model that cannot match know data, and becomes wildly unpredictable the further out it’s projected is not science at all. Truth is they should throw the models out completely. The biggest problem I have trying to swallow the climate change story is the intentional ignoring of counter data, and out right lies. I’m a simple guy; if you lie about the little things, I won’t believe the big things.

[@AlexisGuethler]

@@Aikidoman06 I will leave others to show you that we are beyond previous cycles in the amount of greenhouse gasses and the speed of warming seen over the last couple hundred years. However, to address the cyclic nature of climate change, I have a question for you. Does cyclicality matter if human societies and the ecosystems we rely on cannot keep up our standard of living at higher temperatures? I have no doubt that eventually the earth will heal itself, and the climate will through a cooling period. My question is, how many of us will be here to see it? We are already experiencing negative impacts of climate change, lives and livelihoods are already being lost.

[@Aikidoman06]

@@AlexisGuethler I think that the climate isn’t changing as fast as or as dramatically as many make it out. I think the thing that will impact it most is the current population decline. I consider that China and India, the biggest offenders, don’t plan to do anything about it, so our efforts are a drop in the bucket. When I was a kid in the 70s we were headed towards an ice age, in the 80s it was global famine, in the 90s the ozone layer was going to get up. I think we and this planet will be fine. I believe a more worth cause is to stop countries from using the oceans as a trash can.