“1.5 to stay alive!” is frequently heard at global climate change negotiations, a rallying cry by negotiators from Small Island Developing States, Arctic Indigenous Peoples, non-governmental organizations and many others. It refers to the upper “safe” limit of global temperature increase – and it’s the main message in a new report just released by the Intergovernmental Panel on Climate Change (IPCC).
The report, which examines the impacts of global warming of 1.5°C above pre-industrial levels, was requested after countries at United Nations Framework Convention on Climate Change (UNFCCC) negotiations reached the historic Paris Agreement in 2015. That agreement contains a commitment to hold “the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels’’ and to try “to limit the temperature increase to 1.5 degrees Celsius."
The IPCC report is based on a consensus around the existing science and contains no new research. The picture it paints is compelling and its main message – that the world has very little time in which to act – is urgent.
The difference between 1.5 and 2 degrees above pre-industrial revolution temperatures may not seem like much, but the impacts of this extra half a degree are significant, according to the report. For example, “Coral reefs are projected to decline by a further 70 – 90% at 1.5°C with larger losses (>99%) at 2°C.”
It is important to also keep in mind that the global average temperature has already risen by around one degree. We’re already seeing the effects of that change: more frequent and more powerful hurricanes, floods, drought and massive forest fires, which have displaced millions of people over the last few years. Changes at the poles are dramatic with the Arctic warming to two or three degrees above the global average leading to a rapid retreat in multi-year sea ice. Mountain glaciers are in retreat around the globe threatening the water supply on which billions depend.
The level of 1.5°C has been described as a “guardrail” – go through it and our civilization may not be able to adapt. There isn’t much room for error – or time for delay given that the rate of current greenhouse gas emissions means the 1.5-degree guardrail could be exceeded by 2030.
If temperatures rise to 2°C all of the world’s existing coral reefs will die out. Global sea-level rise will be around 10 centimetres, exposing another 10 million people to risks of flooding. Ocean temperatures will increase along with ocean acidity, which will threaten the marine environment’s ability sustain life. On land, crops like wheat, maize and rice will be threatened.
The faster the world moves to reducing greenhouse gas emissions, the better chance we will have in averting the worst effects of climate change. The IPCC report shows that quicker CO2 reductions will result in a higher probability of limiting warming to 1.5°C.
The report does not undersell the fact such changes will “require rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems. These systems transitions are unprecedented in terms of scale….” This translates into a fundamental, and costly, shift in the way we live our lives, use energy, travel, etc.
The cost of investing in new technologies and developing a new way of living on the planet will be approximately 2.4 trillion USD or 2.5% of global GDP for the next two decades, the report says. This is higher than the 1% figure in the 2006 Stern Review: The Economics of Climate Change.
But this is much lower than the cost of not acting. It’s worth recalling that Stern looked at formal economic models and estimated “that if we don’t act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever. If a wider range of risks and impacts is taken into account, the estimates of damage could rise to 20% of GDP or more.”
The IPCC report says new policies, new ways of investing, new technologies, and changing energy sources, are vital. The public needs to be better educated and new approaches need to be implemented, “including those that are informed by Indigenous knowledge and local knowledge” because they “can accelerate the wide scale behaviour changes consistent with adapting to and limiting global warming to 1.5°C.”
The Stern Review concluded that investment “in the next 10-20 years will have a profound effect on the climate in the second half of this century and in the next.” The IPCC report should refocus global attention on the task at hand.
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