Heatwaves Will Worsen Without Immediate Net Zero Action

Heatwaves will become hotter, longer, and more frequent if global net zero emissions are delayed, according to new research from the ARC Centre of Excellence for 21st Century Weather and Australia's national science agency, CSIRO.

This study, published in the journal Environmental Research Climate, simulated heatwave responses over the next 1,000 years, examining the effects of delaying net zero emissions between 2030 and 2060. The findings indicate that for countries near the equator, delaying net zero until 2050 would lead to heatwave events breaking current historical records at least once every year.

The research also highlights a critical insight: heatwaves will not revert toward preindustrial conditions for at least a millennium after achieving net zero, challenging the belief that conditions will improve quickly post-target.

Lead author Professor Sarah Perkins-Kirkpatrick stated, 'We're damned if we do, but we're completely stuffed if we don't.' She emphasized that we are already locked into a certain amount of warming and that stabilizing global temperatures at 1.5 or 2 degrees Celsius would still lead to heatwave impacts that have yet to be experienced.

Perkins-Kirkpatrick noted that delaying net zero for 30 years or longer will exacerbate these impacts. In Australia, political narratives question the value of reaching net zero, with some claiming it is costly and ineffective.

However, Perkins-Kirkpatrick argues that the costs of not achieving net zero by 2050 would be even greater. The silver lining, she suggests, is that there is time to adapt to these extreme heat conditions, allowing for preparations to mitigate health, ecosystem, and financial impacts.

The modeling utilized Australia's global climate simulator, Access, defining a heatwave as three consecutive days above the 90th percentile for maximum temperature. Professor David Karoly, a noted climate scientist, acknowledged the findings as unsurprising, reinforcing the clear link between cumulative carbon dioxide emissions and global temperatures.

However, he cautioned that there are uncertainties in the model regarding rainfall changes due to its lower geographical resolution compared to other simulators.