Calculating Climate Impacts

Rapid Climate Breakdown. Earth’s systems are breaking down at astonishing speed.  Polar ice melting much faster than expected. Summer meltwater poured in torrents from Greenland's ice cap.  Andrew Freedman and Jason Samenow’s Washington Post article reports that the melting on 31 July 2019 outpaced all data collected since records began in 1950. Daily losses are 50 years ahead of schedule; they were forecast in the climate models for 2070. A paper in Geophysical Research Letters reveals that the thawing of permafrost in the Canadian High Arctic now exceeds the melting scientists expected in 2090. 

To achieve net zero – emissions shouldn't add to the global temperature rise.  There's a serious risk of passing a tipping point (of irreversible change) if our emissions increase global warming over the next 20 years, even if some of the effect is much smaller over longer periods of time. 

Burning biomass for energy releases a pulse of CO2, and in many cases also methane and black carbon, all of which immediately start to warm the planet.  This leads to higher temperatures and more melting of glaciers, polar ice and methane released from permafrost and sub-sea ice – a positive feedback mechanism that leads to further increases global temperatures, melting ice and so on until.  By the time new biomass has grown to replace what was burned, the positive feedback mechanisms will have created higher temperatures and we’ll be closer to the tipping point than if no biomass burning had taken place.

Other Insights from calculating 20-year Climate Impacts

 'Gas-led' recovery obviously flawed! A 'gas-led recovery' might seem plausible if we mistakenly believe that the climate damage is spread over 100 years.  In reality, the impact of methane leaks from fracking and infrastructure happens in the first 20 years, creating potentially dangerous increases in temperature and serious risks of passing tipping points.

Destroying forests for biomass power obviously counter-productive! Methane, black carbon, CO and CO2 from burning biomass pose a similar risk. More than 500 top scientists and economists appealed in February 2021 to stop burning forest biomass for electricity because it's dirtier than burning coal. They argue one of the best ways to curb climate change and sequester carbon is to allow forests to keep growing

More important to eat less red meat. The 2.1 million tonnes of CH4 emitted in 2014 by enteric fermentation of Australian livestock will warm our planet over the next 20 years as much as the 182 million tonnes of CO2-equivalent emitted by Australian electricity and heat production.   The problem could be solved using red algae (Asparagopsis taxiformis) as a feed supplement.  But until this happens, encouraging a switch to other forms of protein could reduce global warming by as much as switching to renewable energy. 

More encouragement to store carbon in trees and biomass. Better accounting procedures would consider the climate damage in the 20 years after emission, count all emissions (including biomass burning) and give climate credits for growing trees, or other biomass. As well as reducing the immediate risk, more informative accounting procedures could lead to better ways of mitigating the climate damage, one possibility being wood harvesting and storage.

Better understanding of the climate impact of methane, black carbon, CO and CO2 from wood stoves. As well as the predicted 0.18–0.26 °C reduction in global warming by 2040 better accounting procedures might also help ordinary folk understand that the methane, black carbon, CO and  CO2 emissions from burning two to four tonnes of wood in an enclosed wood heater will, in the 20 years after emission, contribute as much to the global temperature increase as 15 to 31 similar households heating their homes with efficient reverse cycle heat pumps. 

Does wood bioenergy help or harm the climate?  "the first impact of wood bioenergy is to increase the carbon dioxide in the atmosphere, worsening climate change. Forest regrowth might eventually remove that extra carbon dioxide from the atmosphere, but regrowth is uncertain and takes time – decades to a century or mor e, depending on forest composition and climatic zone – time we do not have to cut emissions enough to avoid the worst harms from climate change." (Sterman et al., Bulletin of the Atomic Scientists, 2022).