In May 2011, almost precisely a decade ago, the government-appointed Climate Commission released its inaugural report. Titled The Critical Decade, the report’s final section warned that to keep global temperature rises to 2C this century, “the decade between now and 2020 is critical”.
As the report noted, if greenhouse gas emissions peaked around 2011, the world’s emissions-reduction trajectory would have been easily manageable: net zero by around 2060, and a maximum emissions reduction rate of 3.7% each year. Delaying the emissions peak by only a decade would require a trebling of this task – a maximum 9% reduction each year.
But of course the decade to 2020 did not mark the beginning of the world’s emissions-reduction journey. Global emissions accelerated before dropping marginally under Covid-19 restrictions, then quickly rebounded.
The Climate Council’s new report, released today, shows the immense cost of this inaction. It is now virtually certain Earth will pass the critical 1.5? temperature rise this century – most likely in the 2030s. Now, without delay, humanity must focus on holding warming to well below 2?. For Australia, that means tripling its emissions reduction goal this decade to 75%.
Aim high, go fast
The Climate Council report is titled Aim High, Go Fast: Why Emissions Need To Plummet This Decade. It acknowledges the multiple lines of evidence showing it will be virtually impossible to keep the average global temperature rise to 1.5C or below this century, without a period of significant overshoot and “drawdown”. (This refers to a hypothetical period in which warming exceeds 1.5C, then cools back down due to the removal of carbon dioxide (CO2) from the atmosphere.)
The increasing rate of climate change, insights from past climates, and a vanishing carbon budget all suggest the 1.5C threshold will in fact be crossed very soon, in the 2030s.
There is no safe level of global warming. Already, at a global average temperature rise of 1.1C, we’re experiencing more powerful storms, destructive marine and land heatwaves, and a new age of megafires.
As the Intergovernmental Panel on Climate Change has warned, the consequences of breaching 1.5C warming will be stark. Heatwaves, droughts, bushfires and intense rain events will become even more severe. Sea levels will rise, species will become extinct and crop yields will fall. Coral reefs, including the Great Barrier Reef, will decline by up to 90%.