Australian bushfires have led to global increase in CO2 levels

During the year the atmospheric concentration of CO₂ is expected to peak above 417 parts per million (ppm) in May, while the average for the year is forecast to be 414.2 ± 0.6ppm.

This annual average represents a 2.74 ± 0.57ppm rise when compared to 2019. While manmade emissions also caused CO₂ to rise in concentration, impacts of weather patterns on global ecosystems are predicted to increase the rise by 10 per cent this year, with emissions from the Australian bushfires contributing up to one-fifth of this increase.

“A forecast of the atmospheric concentration of carbon-dioxide shows that 2020 will witness one of the largest annual rises in concentration since measurements began at Mauna Loa, in Hawaii, 1958,” the Met Office said in a statement.

Weather patterns linked to year-by-year swings in Pacific Ocean temperatures are known to affect the uptake of carbon-dioxide by land ecosystems. 

In years with a warmer tropical Pacific, many regions become warmer and drier, which limits the ability of plants to grow and absorb CO₂ and increases the risk of wildfires, which release further emissions.

Along with other weather patterns and human-induced climate change, this has contributed to the recent hot, dry weather in Australia, which played a key role in the severity of the bushfires.

Professor Richard Betts of the Met Office Hadley Centre and University of Exeter, said: “Although the series of annual levels of CO₂ have always seen a year-on-year increase since 1958, driven by fossil-fuel burning and deforestation, the rate of rise isn’t perfectly even because there are fluctuations in the response of ecosystem carbon sinks, especially tropical forests. Overall these are expected to be weaker than normal for a second year running.”

Concentrations of CO₂ in the Earth’s atmosphere have already far surpassed what scientists consider to be safe limits.

At a climate summit in Madrid in December, UN Secretary-General Antonio Guterres warned that 400ppm had once been considered “an unthinkable tipping point”.

The last time there was a comparable concentration of CO₂ in the atmosphere was between three and five million years ago, when the temperature was between 2°C and 3°C warmer and sea levels were 10 to 20 metres higher than today, scientists say.

Australia’s fires are themselves a foretaste of the kind of catastrophes that are liable to become normal as the planet warms, with prolonged drought and low humidity making arid landscapes more vulnerable to huge blazes, scientists say.

Last month, the 2020 Climate Change Performance Index rated Australia as one of the worst performers among 57 high-emitters, awarding it 0 out of 100 possible points for its policies.

Yesterday the Committee on Climate Change called on the UK government to make substantial efforts to shift land use across the UK and change people’s eating habits in order to lower overall carbon emissions.