Global temperature rises must be limited to no more than 1.5°C above pre-industrial levels within 12 years to avoid a significant worsening of the impacts of climate change, according to a key report released by the UN Intergovernmental Panel on Climate Change (IPCC) today (8 October).
The report was compiled by 91 authors following the review of over 6,000 scientific documents, and was prepared under the scientific leadership of all three IPCC working groups. Working Group I assesses the physical science basis of climate change, Working Group II addresses impacts, adaptation and vulnerability, and Working Group III deals with the mitigation of climate change.
The report states that the risk of increased floods, droughts, heat, food insecurity, and deterioration of the livelihoods of millions of people around the world, would increase dramatically if temperatures rose even half a degree beyond 1.5°C to 2°C, the upper limit agreed by nations in the Paris Climate Agreement of 2016.
Action must be taken immediately, however, as the World Meteorological Organisation warned last week that temperature increases have already risen to around 1.1°C above pre-industrial levels.
Commissioned during the Paris climate talks in 2016, the IPCC report will provide key input into the Katowice climate change conference in Poland in December. It is stated that every additional increase in temperature worsens the impact of climate change, but that a 1.5°C rise would lower exposure to water scarcity by 50 per cent compared to a 2°C increase, while insects and plants would be twice as likely to lose up to half of their habitats with a 2°C temperature rise.
Looking at the oceans specifically, a temperature increase of 2°C would bring about the loss of 99 per cent of corals, while marine fisheries could lose three million tonnes of stock. Rising seas levels would affect 100 million more people by 2100 and ice-free summers in the Arctic would be 10 times more likely than at an increase of 1.5°C.
“Every extra bit of warming matters, especially since warming of 1.5ºC or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,” explained Hans-Otto Pörtner, Co-Chair of IPCC Working Group II.
Is a 1.5 degree limit possible?
In order to limit temperature rises to 1.5°C, the IPCC report states that by 2030, CO2 emissions would have to decline by 45 per cent from 2010 levels, reaching net zero by 2050, while ‘rapid and far-reaching’ transitions in energy, land, urban, infrastructure and industrial systems would have to be made on an ‘unprecedented’ scale.
Reforestation and carbon capture on a vast scale would have to take place, while untested carbon dioxide removal technology would have have to be implemented to bring carbon emissions back into a 1.5°C range if this were to be exceeded.
Above all, the report stresses the need for urgency and a continuation of the progress made so far. While the uptake of renewable energy has seen a considerable increase in recent years, countries such as the UK are pushing ahead with fracking projects while others, like Norway, are continuing new oil exploration projects. Meanwhile, deforestation for agricultural purposes continues unabated, removing woodland that acts as a natural carbon sink. Furthermore, the current international commitments in place, if honoured, will only limit warming to 3°C.
Commenting on the report, Jim Skea, Co-Chair of IPCC Working Group III, said: “We have presented governments with pretty hard choices. We have pointed out the enormous benefits of keeping to 1.5°C, and also the unprecedented shift in energy systems and transport that would be needed to achieve that. We show it can be done within laws of physics and chemistry. Then the final tick box is political will. We cannot answer that. Only our audience can – and that is the governments that receive it.”
The political will to implement the drastic changes needed appears to be the largest stumbling block, with some countries turning away from their international commitments – including the US, under the leadership of climate-sceptic Donald Trump, who withdrew the US from the Paris Climate Agreement, and Brazil, which looks set to elect as its new president far-right candidate Jair Bolsonaro, who is committed to opening the Amazon rainforest to agrobusiness.
Despite the bleak picture presented if the required action is not taken, authors of the report and the scientific community retain hope that the international community and national governments will heed the warnings and work to prevent catastrophic temperature increases.
Responding to the IPCC's report on, Green Party MP Caroline Lucas said: "This report couldn't be written in stronger terms: we are at a tipping point on the edge of complete climate breakdown, and governments around the world are failing to prevent it.
"Our own government is pushing us towards that tipping point with carbon intensive and ecologically destructive projects like airport expansion, fracking and HS2 – while slashing support for renewables and continuing to subsidise fossil fuels.
"Ministers have a choice: they can keep coating business-as-usual policies in a green veneer and watch as floods and heatwaves become the norm. Or they can embrace the opportunities to create a fairer, healthier, safer society that come with the economic overhaul we need."