GreenARC

Calculating Climate Impacts

Rapid Climate Breakdown - serious risk of passing tipping points in less than 100 years

Earth’s systems are breaking down at astonishing speed. Summer meltwater pours in torrents from Greenland's ice cap. Andrew Freedman and Jason Samenow’s Washington Post Report noted that the melting on 31 July 2019 outpaced all data collected since records began in 1950. Daily losses are at levels climate models forecast for 2070, i.e. 50 years ahead of schedule.

A paper in Geophysical Research Letters reveals that the thawing of permafrost in the Canadian High Arctic now exceeds the melting scientists expected to happen in 2090.

Huge wildfires burned across the Arctic, releasing more carbon dioxide in 2019 than in any year since satellite records began nearly two decades ago. According to the World Meteorological Organisation: "A recent study found Earth’s boreal forests are now burning at a rate unseen in at least 10,000 years.”

Climate change was a key factor in Australia's devastating 2019-20 fires that resulted in 417 premature deaths in Eastern Australia and released an estimated 830m tonnes of CO₂, more than all except the 5 most polluting countries in the world.

Current Warming is Increasing Future Warming

The Arctic and Antarctic are warming faster than the global average rate. When polar ice melts, it absorbs radiation instead of reflecting it back into space. Methane (which traps 86 times as much heat in the first 20 years after emission as the same weight of CO₂) is released when permafrost and undersea ice melt, and this adds to future warming, as does CO₂ from wildfires.

Huge wildfires and unexpectedly fast melting are just part of the mounting evidence (such as methane blow-holes in Siberia) that we need to take urgent action to tackle the Climate Emergency, or risk passing a tipping point (i.e. a point of no return). Berkley Earth's Global Temperature Report for 2020 predicts that global warming will exceed 1.5°C by 2037.

To achieve net zero – emissions shouldn't add to the global temperature rise

'Net Zero' emissions should mean no contribution to increased global temperatures, even short-term increases. Otherwise, the risk of passing a tipping point (of irreversible change) increases. Current warming increases future warming, already expected to exceed 1.5°C by 2037. The Intergovernmental Panel on Climate Change (IPCC) strongly recommends limiting the global temperature increase to 1.5°C, to avoid steeply escalating impacts of climate change. The Australian Climate council warns that even at 1.5°C of global warming, times will be tough, with impacts amplifying rapidly between 1.5°C and 2°C.

Burning biomass for energy releases a pulse of CO₂, and often methane and black carbon, all of which immediately start to warm the planet. This leads to higher temperatures and more melting glaciers, polar ice, permafrost and undersea ice, and the release of more methane – a positive feedback mechanism that leads to even more temperature increases, melting ice, methane release, and so on. 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.

Calculators should compare greenhouse impacts over 20 years

Although CO₂causes the most warming –1.68 W/m² (watts per square metre), the diagram from the US EPA report: Methane and Black carbon, impacts on the Arctic shows that methane (CH₄, radiative forcing of 0.97 W/m², which includes the warming of ground-level O₃ formed from CH₄) and black carbon (0.88 W/m²) together cause more warming than CO₂.

Methane and black carbon are known as super-pollutants or short-lived-climate-pollutants (SLCP), because they cause substantial amounts of global warming, but rapidly disappear from the atmosphere, if we stop emitting them, creating rapid climate benefits

Consequently, to maximize our chances of avoiding a disastrous climate tipping point, greenhouse calculators should account directly for all climate impacts using the IPCC’s global warming potentials (GWP) over 20 years, including CO₂ absorbed by planting trees, methane emitted from fracking and leaking gas infrastructure, and methane, black carbon and CO₂, emitted by burning biomass.

Temperatures 0.25°C to 0.5°C lower by 2040

By considering the impact over the next 20 years - a critical period if we are to avoid climate tipping points - we'll do a better job of slowing the global temperature rise as quickly as possible, buying time, to develop and implement the best possible long-term strategies as technology changes and improves, including growing biomass to eventually remove excess CO₂from the atmosphere and return to a safe, stable climate.

Analyses by UNEP 2011; Ramanathan and Xu 2010; Shindell et al. 2012; Hu et al. 2013 concluded that targeting SLCP emissions could reduce warming by around 0.5 °C. In 2020, researchers modelled the combined effect of reducing emissions of CO₂, methane and black and organic carbon (BC and OC) using the best available technology for transportation and phasing-out direct use of biomass and coal in residential and commercial buildings.

The measures to reduce CO₂ methane, BC and OC were estimated to avoid a further 0.18–0.26 °C in 2040 compared to just reducing CO₂, demonstrating the substantial benefits of considering all greenhouse pollutants including the immediate impact of SLCP, instead the much smaller benefit if the climate effect of SLCP emissions is averaged over the next 100 years.

What we'd do differently ...

'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. There'd also be increasing recognition that heat pumps (that can deliver 5 times as much heat to our homes as they use in electric power) running off renewable electricity have much lower costs and cause a lot less global warming.

Destroying forests for biomass obviously counter-productive! Methane, black carbon, CO and CO₂from burning biomass pose a similar risk to gas. 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. Perhaps the problem will 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.

Encourage storage of carbon in trees and biomass. Better accounting procedures would quantify 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, including restorative agriculture and wood harvesting and storage.

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 CO₂emissions 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.

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