Calculations of global carbon budgets have underestimated potential increases in global temperatures, and the world will have to dramatically accelerate its decarbonisation efforts, a new analysis of climate projections has argued.
According to a new briefing note published by the National Centre for Climate Restoration, also known as Breakthrough, carbon budgets calculated by authorities like the Intergovernmental Panel on Climate Change (IPCC) are virtually meaningless due to a failure to adequately account for feedback effects, and are likely to lock in higher temperature increases.
The paper paints a grim picture of the chances to achieve global warming limits enshrined in the Paris Agreement, in which countries agreed to goals of limiting warming to no more than 2°C above pre-industrial levels, and striving to limit to no more than 1.5°C.
“The world is likely entering a period of accelerated warming, and reducing emissions will have little or no effect on that trend for the next 20-25 years. The imminence of further tipping points makes this a wicked problem, because 2°C is far from safe,” the paper says.
To ensure a realistic chance of limiting global warming to no more than 2 degrees, Breakthrough suggests that zero net emissions will need to be achieved by industrialised countries before 2030.
The briefing paper points to research that suggests global warming is already on track to cause warming of 1.5°C, regardless of global emissions reduction efforts.
The briefing paper was prepared by Breakthrough’s research director David Spratt, and former coal industry executive and chairman of the Australian Coal Association, Ian Dunlop.
The authors argue that carbon emissions budgets for limiting global warming to just 1.5 degrees were meaningless, as the world was already on an ‘overshoot’ trajectory, temperatures will exceed the temperature target, requiring large volumes of carbon capture and storage.
The analysis also says that the probabilities included within carbon budgets calculated by organisations like the IPCC present an unacceptable risk of failure, given the potentially catastrophic impacts of rising temperatures.
“IPCC carbon budgets are often associated with a 50 or 66% chance of staying below the target, that is, a one-in-two, or one-in-three, chance of failure, for example in the IPCC Fifth Assessment Report and the 2018 Special Report on Global Warming of 1.5°C. We would never accept those risks of failures in our own lives. Why accept them for impacts which may destroy civilisation as we know it?” the paper says.
“The IPCC carbon budgets are reckless in their approach to risk. If a prudent risk management approach is taken, there is no carbon budget for the 2°C goal. This further emphasises the importance of reaching net zero emissions before 2030.”
The briefing paper says that efforts to calculate a global emissions budget have underestimated the impacts of feedback effects, which will work to accelerate the rate of global warming. These feedback effects include the release of methane from melting permafrost and the loss of albedo, or reflectivity, across the earth’s surface.
The briefing suggests that many of the targets being adopted by Australian businesses will fall short of what is needed to address the “realities” of climate change.
“In Australia, business is focussing on a target of zero emission by 2050. Many large climate advocacy organisations have fallen into supporting this policy. Others have picked nearer term targets, such as zero emissions by 2035, or 75% emissions cuts by 2030,” the briefing paper says.
“The evidence shows that none of these policies accord with the physical realities for a country such as Australia, which has amongst the highest per capita emissions in the world, alongside the USA and some Gulf states. As demonstrated below using over-optimistic IPCC figures, and with an equal per capita approach, Australia’s budget for 2°C with a one-in-three risk of failure, expires in 2026.”
The conclusions of the paper mirror the findings of analysis published by a number of prominent climate science and policy researchers under the banner of a new independent ‘Climate Targets Panel’.
Recently published analysis by the Climate Targets Panel similarly suggested that Australia would need to achieve zero net emissions by 2035, as part of a combined global effort, if there was to be any hope of limiting warming to just 1.5 degrees.
Data published by NASA and NOAA in January showed that 2020 was effectively tied with 2016 for the warmest year on record. The scientific agencies estimated that global temperatures had increased by 1.2 degrees Celsius since the late 19th century.
The Australian Academy of Science has also published its own analysis, outlining the potential impacts of the world’s current trajectory towards 3 degrees of global warming.
Expected impacts, based on the current trajectory, include the potential for complete devastation of the Great Barrier Reef.
