Code red for humanity – How real is the threat of climate change?

Written by Divya Narayan

The global contribution of CO2 between 1990 and 2021 accounts for 41% of all CO2 released since 1750, according to the head of the Global Carbon Project.[1]

The Paris Agreement is the most recent binding international treaty on climate change.[2] It requires parties to limit the increase in global average temperature to 2°C (preferably 1.5°C) above pre-industrial levels, and reach net-zero emissions by the second half of the century.[3]

IPCC report

The Intergovernmental Panel on Climate Change (IPCC) is a body established in the 1980’s by the United Nations to investigate and assess the science relating to climate change.[4]

"It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred."[5]

The August 2021 IPCC report is the contribution of Working Group 1 to the IPCC’s sixth assessment report. One key takeaway is the IPCC’s prediction of global emissions in 5 different scenarios. Some options are predicated on strict and immediate restrictions on emissions to be implemented, while others are calculated on continually high emission rates until the end of the century. The data used to manufacture these scenarios is derived from the development of anthropogenic drivers of climate change found in scientific literature.[6] Based on these assessments, 2°C will be exceeded during the 21st century under the high and very high GHG emission scenarios (SSP3-7.0 and SSP5-8.5 respectively), and extremely likely to be exceeded under the moderate (SSP2-4.5) prediction.[7] Under the low and very low projections (SSP1-2.6 and SSP1-1.9 respectively) the warming of 2°C is extremely unlikely to be exceeded. In the best case scenario, if the world could keep global temperatures under a 1.6°C increase by 2041-2060, and a 1.4°C increase by 2081-2100.[8] In comparison, the trajectory for highest emissions means the world may warm by 4.4°C by 2100.[9]  

Even under the lowest emissions scenario, global temperatures are likely to exceed the 1.5°C threshold before coming down at the end of the century.[10]

One of the impacts of rising temperature is the increased frequency and severity of extreme weather events, and an increase in ‘compound events, such as heatwaves and long-term droughts occurring simultaneously’.[11] This threatens the security of people’s lives and could render hundreds of millions of people homeless and dispersed.[12]

Of the 1.1°C warming we have seen since the pre-industrial era, the IPCC Report finds that less than 0.1°C is due to natural forces such as volcanoes or variations in the sun, and the remainder from anthropogenic contributions.[13]  So, how much is being done by Australia to combat climate change?

Australia’s commitments

Australia first committed in 2015 to a reduction of 26-28% below 2005 levels by 2030 upon joining the Paris Agreement. Placing this in context, our counterparts in the EU are aiming for a 40% reduction of emissions by 2030 and the US have committed to a 26-28% reduction by 2025.[14] With the current policies in place in Australia (per 2018 data), Australia “will not meet its 26-28% emissions reduction target”.[15] “If all other countries were to have similar climate policies to Australia’s, then global average temperatures could reach for 3°C and up to 4°C above pre-industrial levels.[16]

Conclusion

Each country is allocated a certain carbon budget based on their share of the global population. The global carbon budget is the amount of CO2 that can be ‘spent’ over the coming years to maintain the global goal of remaining below a 2°C increase in temperatures. The world’s carbon budget was calculated based on an overall budget of 1000Gt. The world has ‘spent’ an estimated 575 Gigatons (Gt), leaving us with 425 Gt before the world needs to reach net zero.[17] Based on global share of population, Australia’s share is 5,500 Mt of CO2. If emissions continue at this rate, we have barely 10 years before our remaining carbon budget is completely exhausted.[18]

The IPCC report adds a great breadth of scientific analysis and data to reinforce the importance of immediate action by countries to curb their emissions sooner rather than later. The next world summit for Climate Change is the COP26 climate change conference in Glasgow, Scotland, and countries will be expected to renew and reinvigorate their pledges to cut GHG emissions to ensure net zero is achieved across the globe before 2050. [19]

Only time will tell what kind of action Australia will take.

[1] Michael Slezak, ‘The IPCC has released the most comprehensive report ever. Here’s what you need to know’, ABC News (online, 10 August 2021) https://www.abc.net.au/news/2021-08-10/coal-climate-change-covered-in-ipcc-reports-key-questions/100355954.

[2] Paris Agreement, opened for signature 22 April 2016 , [2016] ATS 24 (entered into force 4 November 2016) (‘Paris Agreement’).

[3] Ibid art 2(1); 2(1)(a).

[4] ‘About the IPCC’, Intergovernmental Panel on Climate Change (IPCC) (website, 2021) https://www.ipcc.ch/about/.

[5] IPCC, ‘Climate Change 2021: The Physical Science Basis. Summary for Policy Makers’, Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, (2021) 6 (‘IPCC Report’).  

[6] Ibid 16.

[7] IPCC Report (n 5) 18.

[8] Ibid.

[9] Ibid.  

[10] Jeff Tollefson, ‘EARTH IS WARMER THAN IT’S BEEN IN 125,000 YEARS, SAYS LANDMARK CLIMATE REPORT’, Nature (2021) 596 Nature 171-172, 172.

[11] IPCC Report (n 5) 24.

[12] Tollefson (n 10) 172.

[13] IPCC Report (n 5) 6.

[14] Climate Change Authority, ‘Comparing Countries’ Emission Targets’ Climate Change Authority https://www.climatechangeauthority.gov.au/comparing-countries-emissions-targets.

[15] Climate Council, ‘Australia’s Rising Greenhouse Gas Emissions (Report, 2018) 4.

[16] Ibid 1.

[17] Climate Council (n 16) 9.

[18] Ibid.

[19] Slezak (n 1).