An opinion piece by Dr Hugh Montgomery, Professor of Intensive Care Medicine; Director, University College London’s Centre for Human Health and Performance Co-Chair Lancet Countdown on Health and Climate Change 

Global heating is caused by human activity. Building and construction account for nearly 40% of global carbon dioxide (CO2) emissions. Over a quarter of this comes from the manufacture of building materials and the remainder from building operations such as lighting and heating.

The resulting climate change no longer represents a vague and ethereal threat to ‘our grandchildren’ or to ‘future generations’. The threat is to us and to our children alive today. The only question is whether each of us will take responsibility when others have not.

Nearly three decades of these international meetings and negotiations have made no difference at all to the continued rise in greenhouse gas emissions, which rose by 6% in 2021 alone(1).

The energy equivalent of many tens of billions of Hiroshima Bombs has been trapped since 1990 alone(2), the bulk in our oceans. Global temperatures are rising, ice is melting (summer Arctic sea ice volume fell by three quarters, or 12,723 cubic kilometres, from 1979-2019(3) and the Greenland ice sheet alone loses >1 billion litres of meltwater/minute(4) and sea levels rising (by nearly 4.5 cm in only 16 years(5)). Extreme weather events- floods, fires, droughts and storms- are ever more frequent and severe. In 2021, temperatures in Arctic Verkhojansk breached 48 °C(6) and approached 50 °C in Canada.(7) In March 2022, Antarctic temperatures were fully 47oC higher than average, and those in the Arctic 30oC higher(8). Last year, fires raged worldwide, from Canada and California to Italy and Indonesia, Spain and Siberia.

Positive feedback loops are now amplifying energy gain. Snow and ice melt means less reflection of shortwave radiation back into space. As a result, Earth’s energy imbalance has doubled in only 14 years.(9) Arctic tundra melt is releasing methane, >80x as powerful a greenhouse gas as CO2 in its first 2 decades(10), and is also ablaze releasing more CO2(11). Carbonate rocks are now warming and releasing methane(12). Wildfires add CO2 to the atmosphere- that in Eastern Australia in the northern hemisphere winter of 2020/21 alone added 2% to global emissions, and the fires of 2021 added over 1.7 billion tonnes
of carbon ( 6.5 billion tonnes, or over 3000 trillion litres, of CO2) to the atmosphere(13). The Amazon is now a net emitter of CO2(14).

For forty years, we have ignored repeated warnings. We now reach a point of decision and consequence. Antarctic heating alone now threatens ‘everything we value that sustains us’.(15,16). As the world’s scientists of the Intergovernmental Panel on Climate Change now say, without concerted and immediate action, we miss ‘missing a rapidly closing window to secure a liveable future’(17).

Limiting global temperature rise to a further 25 % of that already seen (to 1.5 °C) is, of course, nowhere near safe given that the changes we already experience will only worsen. But even this now requires not only the rapid cessation of all emissions but massive drawn-down of CO2 from our atmosphere. Even then, ‘climate changes would continue in their current direction for [up to] millennia’ and it could take ‘millennia… for global mean sea level to reverse course.’(18)

All plants and animals depend upon a stable and narrow range of environmental conditions to thrive and survive. By changing background ‘stable’ temperature and water availability, such survival is threatened: over the next 50 years, ‘1 to 3 billion people are projected to be left outside the climate conditions that have served humanity well over the past 6,000 y, [and without action] a substantial part of humanity will be exposed to mean annual temperatures warmer than nearly anywhere today”(19). Rising seas and extreme weather events further threaten viability.

Building and construction account for 39% of global carbon dioxide (CO2) emissions- 28% due to the manufacture of building materials, and 11% from building operations such as lighting and heating(20).
We all have a responsibility to change our practices to address this. At once. Yes, this will be disruptive. Yes, it will be hard. But these are challenges we must step up to face. Our lives, and those of our children, depend upon it.

References
1. International Energy Authority https://www.iea.org/news/global-co2-emissions-rebounded-to-their-highest-level-in-history-in-2021 accessed 1st May 2022
2. NASA Global Climate Change, Ocean Heat Content (2021) [Accessed 1st May 2022] https://climate.nasa.gov/vital-signs/ocean-heat/
3. Yadav J, Kumar A, Mohan R, Dramatic decline of Arctic sea ice linked to global warming. Nat Hazards. 2020 Sep 1;103(2):2617–21
4. Sasgen I, Wouters B, Gardner AS, et al., Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites. Communications Earth & Environment. 2020 Aug 20;1(1):1–8
5. NASA Global Climate Change, Sea Level, (2021). [accessed May 1st 2022]. Available from: https://climate.nasa.gov/vital-signs/sea-level/
6. Land Surface Temperature in the Sakha Republic (2021). [accessed 2021 Aug 10]. Available from: https://www.copernicus.eu/en/media/image-day-gallery/land-surface-temperature-sakha-republic
7. Record-breaking heat in Canada (2021). [Accessed 1st May 2022]. Available from: https://www.rmets.org/metmatters/record-breaking-heat-canada
8. Available at https://www.severe-weather.eu/global-weather/powerful-heatwave-affecting-antarctic-continent-unprecedented-temperatures-40-degrees-above-average-rrc/ [accessed May 1st 2022]
9. Loeb NG, Johnson GC, Thorsen TJ, et al., Satellite and ocean data reveal marked increase in earth’s heating rate. Geophys Res Lett [Internet]. 2021 Jun 15 https://doi.org/10.1029/2021GL093047
10. Walter Anthony K, Schneider von Deimling T, Nitze I, et al., 21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes. Nat Commun. 2018 Aug 15;9(1):3262.
11. Witz, A. The Arctic is Burning Like Never Before- and its bad news for Climate Change Nature 2020 available at https://www.nature.com/articles/d41586-020-02568-y [accessed May 1st 2022]
12. Froitzheim N, Majka J, Zastrozhnov, D. Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave. PNAS 2021, 118 (32) e2107632118 available at https://www.pnas.org/content/118/32/e2107632118 [accessed May 1st 2022]
13. Available at https://atmosphere.copernicus.eu/wildfires-wreaked-havoc-2021-cams-tracked-their-impact [accessed May 1st 2022].
14. Covey, K et al. Carbon and Beyond: The Biogeochemistry of Climate in a Rapidly Changing Amazon Front. For. Glob. Change, 11 March 2021 Available at https://www.frontiersin.org/articles/10.3389/ffgc.2021.618401/full [accessed May 1st 2022]
15. Clem KR, Fogt RL, Turner J, et al., Record warming at the South Pole during the past three decades. Nat Clim Chang. 2020 Jun 29;10(8):762–70.
16. Jansen E, Christensen JH, Dokken T, et al., Past perspectives on the present era of abrupt Arctic climate change. Nat Clim Chang. 2020 Jul 29;10(8):714–21
17. IPCC Press Report, available at https://www.ipcc.ch/report/ar6/wg2/resources/press/press-release/ [accessed May 1st 2022]
18. IPCC 6th Assessment Report: AR6 Climate Change 2021: The Physical Science Basis Available at https://www.ipcc.ch/report/ar6/wg1/ [accessed May 1st 2022]
19. Chi Xu, Timothy A. Kohler, Timothy M. Lenton, Jens-Christian Svenning, and Marten Scheffer Future of the human climate niche PNAS May 26, 2020 117 (21) 11350-11355
20. Global Staus Report 2017; Published by UN Environment and the International Energy Agency Available at https://www.worldgbc.org/sites/default/files/UNEP%20188_GABC_en%20%28web%29.pdf [accessed May 1st 2022]