Important scientific papers are coming out every week providing up-to-date information on all aspects of the global climate emergency. Current extreme weather events (extreme rainfall, drought and dry heat as well as dangerous combinations of heat and high humidity, such as occurred during the Tokyo Olympics) and their consequences (flooding, glacial and polar ice melting, low river and lake levels and wildfires) are more likely with human-induced global heating. All this and the very clear conclusions of the sixth Intergovernmental Panel on Climate Change – IPCC – Assessment Report (Climate Change 2021 – Working Group I – The Physical Science Basis), mean that policy makers are going to find it increasingly difficult to ignore or diminish the climate emergency and to delay climate action.

The main findings of the IPCC report are:

• That it is unequivocal that human influence has warmed the atmosphere, ocean and land resulting in wide-scale, rapid changes in the atmosphere, ocean, cryosphere (glaciers, polar ice and permafrost) and biosphere (where living organisms, including humans, occur!).
• Human-induced climate change is already affecting many weather and climate extremes in every region all over the world via heatwaves, heavy precipitation, droughts, and tropical cyclones, and the attribution of human activity to these events has strengthened since the last assessment report in 2013.
• The latest improved scientific information gives a best estimate of equilibrium climate sensitivity of 3°C, that is, by how much global temperatures will likely rise in response to human-induced CO₂ emissions (Hausfather, 2018) and this is estimated to have a narrower likely range (2.5°C to 4°C) than the previous report (1.5°C to 4.5°C, with no best estimate). However, temperatures will reach 1.5°C above the pre-industrial (1850-1900) levels by 2040 in all the greenhouse gas emission scenarios. That is 10 years earlier than previously expected.

The IPCC Summary for Policymakers is well worth a look for more details if you don’t fancy the 3 thousand odd pages in the full report. See also Ripple et al. 2021, an excellent, short and easy to read paper warning on the climate emergency (especially Figures 1 and 2). The indicators are clear and too little is being done to eliminate greenhouse gas emissions, despite warnings decades ago of the unprecedented consequences for the planet of the continued use of fossil fuels. Even more extreme weather events will become more frequent, being related to the rate of climate warming and thus greenhouse gas emissions (Fischer et al. 2021). More frequent extreme episodes of heat and humidity present a significant challenge to humans (Raymond et al. 2020). The extreme weather events and their consequences are certainly drawing a lot of attention but how much of this interest will translate into real, transformative action to combat the climate emergency?

The COVID-19 pandemic has shown that we can reduce our greenhouse gas emissions and other impacts on the planet via extraordinary changes in our behaviour and consumption. Examples include taking holidays locally, making homes more energy efficient, avoiding fast fashion, walking, biking or using public transport instead of a car, reducing meat consumption, and so on. Unfortunately, recent data (Ripple et al. 2021) show a resumption of harmful activities in 2021, stimulated by the desire of many businesses and governments to return to a business-as-usual scenario.

Governments, businesses and the public urgently need to cooperatively transform the economy by decarbonizing human activity and investing in clean, renewable energy and industrial, agricultural and leisure activities with minimal impacts on the natural world. We also need to invest in and increase nature protection, natural carbon sinks, green and fair employment, education and family planning, as well as sustainable and accessible housing, and eliminate production of waste and pollution through innovative technology. All this is entirely possible, even within a short time frame of a decade, but a major obstacle is that we need unprecedented global political and economic leadership, willingness and commitment.

Links

Fischer, E.M., Sippel, S. & Knutti, R. 2021 Increasing probability of record-shattering climate extremes. Nature Climate Change 11, 689–695. https://doi.org/10.1038/s41558-021-01092-9

Hausfather, Z. 2018 Explainer: How scientists estimate ‘climate sensitivity’. https://www.carbonbrief.org/explainer-how-scientists-estimate-climate-sensitivity

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. https://www.ipcc.ch/assessment-report/ar6/

Raymond, C., Matthews, T. & Horton, R.M. 2020 The emergence of heat and humidity too severe for human tolerance. Science Advances 6(19), eaaw1838. https://doi.org/10.1126/sciadv.aaw1838

Ripple, W.J. et al. 2021 World scientists’ warning of a climate emergency 2021 BioScience, biab079, https://doi.org/10.1093/biosci/biab079