Climate science informs us that humans have unequivocally caused global warming and details what is driving the warming (Chen et al., 2021, p. 150). For more on that, see my Climate Diagnosis Post. In addition, climate science identifies what planetary systems are changing and what climate impacts are already occurring. More importantly, these impacts can be projected into the future based on how much greenhouse gas is emitted. This gives us a window into various futures depending on our current choices. The troubling part is that in the last 50 years, there has been a rapid increase in greenhouse emissions and, correspondingly, the global surface temperature. Both have risen faster than in any other period in 2000 years (IPCC, 2021, p.8). Also, in the previous 50 years, almost all the world’s glaciers have retreated, which is unprecedented in the last 2000 years. Arctic sea ice has been at its lowest since 1850, and the global mean sea level has risen faster in the last century than any previous one for at least 3000 years. In addition, the increase in sea temperature, oxygen concentrations, and declining global ocean pH (Arias et al., 2021, p.74) all affect the ocean environment, circulation, and coastal shorelines.
Scientists assure us that human-induced climate change has affected every region of the planet with extreme weather and unprecedented climate events (IPCC, 2021, p. 8). Those impacts will increase in frequency, intensity and duration with each incremental degree of warming (IPCC, 2021, p. 18). Although this is alarming, there is more. As warming continues, multiple extreme events will happen simultaneously (IPCC, 2021, p. 25). This will be further exacerbated by the warming rate that increases the occurrence of record-shattering events such as heat waves and droughts (Fischer et al., 2021, p. 692). Figure 2 graphically shows the climate impacts and how they intensify for higher surface temperatures (Arias et al., 2021, p. 89). The warmer it gets, the worse it is and the more inhospitable to human, animal and plant life. There is no motivation to allow warming to rise beyond 1.5°C above pre-industrial levels.
Figure 2
From Arias et al., 2021, p. 89.
As shown in Figure 2, global warming is currently at 1.1oC above preindustrial levels, and the climate impacts on ecosystems and humans have already been widespread, extreme and deadly. To help contextualize this, I found it helpful to think about local impacts. For example, southern Canada is warming at double the global average, with northern Canada warming even faster (Bush et al., 2022, p. 7). The three oceans surrounding Canada have been negatively affected as they warm, lose oxygen below the global average for the Pacific and become more acidic. Regional coastlines are impacted as the global mean sea level (GMSL) rises. Some will have much higher sea levels than the GMSL (Bush et al., p.30). Although precipitation is increasing, this will be from intense rainfall in the winter, while lower rainfall in the summer increases the incidence, duration and intensity of drought (Bush et al., 2022, p.8). Extreme hot temperatures will continue to increase in intensity and frequency, as will heat waves and weather extremes (Bush et al., 2022, p.9). There already is less snowpack, glaciers are rapidly receding, permafrost is thawing, and Arctic Sea ice is melting (Bush et al., 2022, p. 8 & 9). In British Columbia, we have already experienced some significant impacts from climate change, including deadly heat waves, record-breaking wildfire seasons, unprecedented drought, extreme winter storms, heavy unremitting precipitation and devastating floods (MoE, n.d.). It is difficult to imagine it getting worse, but unfortunately, that is the track we are currently on.
But a few things caught my attention as necessary for all to know when we think about climate action. Firstly, every tonne matters, each additional tonne of CO₂ emissions adds to global warming (IPCC, 2021, p. 28), and therefore, each tonne avoided matters. As CO2 is so long living in the atmosphere, our emissions today will be affecting the climate of our great-grandchildren; not a legacy any of us should be leaving, so any effort we make now will make a difference. Secondly, because CH4 has such a high warming potential and is rapidly increasing, getting that under control quickly is essential (Arias et al., 2021, p. 103). We need methane police! Finally, realizing that rapidly reducing GHGs now would make a difference within years and global temperatures would stabilize in twenty years (IPCC, 2021, p. 30) made me wonder why we would want to drag this out any longer than necessary. Getting on this now means most humans alive today will benefit from their efforts. For those that have already experienced climate impacts, that should be motivating.
Note on Citations
The information in the IPCC reports is very dense. To aid in finding the reference for myself, instructors and readers that might want to follow up I have included page numbers.
References
Arias, P.A., N. Bellouin, E. Coppola, R.G. Jones, G. Krinner, J. Marotzke, V. Naik, M.D. Palmer, G.-K. Plattner, J. Rogelj, M. Rojas, J. Sillmann, T. Storelvmo, P.W. Thorne, B. Trewin, K. Achuta Rao, B. Adhikary, R.P. Allan, K. Armour, . . . K. Zickfeld, (2021). Technical Summary. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 33−144, https://doi:10.1017/9781009157896
Bush, E., Bonsal, B., Derksen, C., Flato, G., Fyfe, J., Gillett, N., Greenan, B. J. W., James, T. S., Kirchmeier-Young, M., Mudryk, L., & Zhang, X. (2022). Canada’s changing climate report, in light of the latest global science assessment. https://doi.org/10.4095/329703
Chen, D., M. Rojas, B.H. Samset, K. Cobb, A. Diongue Niang, P. Edwards, S. Emori, S.H. Faria, E. Hawkins, P. Hope, P. Huybrechts, M. Meinshausen, S.K. Mustafa, G.-K. Plattner, and A.-M. Tréguier. (2021). Framing, Context, and Methods. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L., Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R., Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 147–286, doi:10.1017/9781009157896.003.
Fischer, E. M., Sippel, S., & Knutti, R. (2021). Increasing probability of record-shattering climate extremes. Nature Climate Change, 11(8), Article 8. https://doi.org/10.1038/s41558-021-01092-9
IPCC. (2021). Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 3−32, https://doi:10.1017/9781009157896.001
Minster of Environmental & Climate Change Strategy (MoE). (n.d.). Climate Preparedness and Adaptation. Province of British Columbia. Retrieved December 16, 2022, from https://www2.gov.bc.ca/gov/content/environment/climate-change/adaptation#impacts