Wildfires have been burning in Greece in recent days. The world’s largest-ever report on climate change will be published later, setting out the stark reality of the state of the planet. The study is by the Intergovernmental Panel on Climate Change – a UN group that examined 14,000 scientific papers. It will be the most up-to-date assessment of how global warming will change the world in the coming decades. Scientists say it will likely be bad news – but with “nuggets of optimism”.
And environmental experts have said it will be a “massive wake-up call” to governments to cut emissions. The last time the IPCC looked at the science of global warming was in 2013 – and scientists believe they have learned a lot more since then. The world has seen record-breaking temperatures, raging wildfires, and devastating flooding in recent years.
Some papers studied by the panel show that some of the changes humans inadvertently make to the climate will not be reversed for hundreds or maybe thousands of years. The IPCC’s findings – revealed at a press conference at 09:00 BST – will also be used during a major summit the UK hosts in November.
The summit, COP26, which the UN runs, is seen as critical if climate change is controlled. Leaders from 196 countries will meet to try and agree to action. Alok Sharma, the UK minister leading the summit, said at the weekend that the world was almost running out of time to avoid catastrophe – and the effects of climate change were already happening.
Analysis box by Roger Harrabin, the Environment analyst
The intergovernmental panel brings together representatives of world governments who appraise research by scientists. The last meeting was in 2013, and researchers say much has improved. Previously, for instance, they were reluctant to ascribe extreme events such as heatwaves and torrential rain to being at least partly down to climate change. That means all governments buy into the findings.
The panel studied papers showing that the sea level would continue to rise for hundreds or possibly thousands of years because of the deep heat trapped in the ocean. Research confirms that if politicians can stick to holding global temperature increase down to 1.5C in pre-industrial times, the worst catastrophes can still be avoided. Prof Piers Forster, an expert in climate change from the University of Leeds, said the report “will be able to say a whole lot more about the extremes we are experiencing today, and it will be able to be categoric that our emissions of greenhouse gases are causing them and they are also going to get worse”.
“The report will come with quite a lot of bad news about where we are and where we’re going, but there are going to be nuggets of optimism in there which I think are good for the climate change negotiations,” he told LBC.
One of the causes for optimism he mentioned was that there is still a chance of keeping global warming below 1.5 degrees. Experts say the impacts of climate change are far more severe when the increase is more significant than 1.5C. So far, global temperatures have climbed to 1.2C above pre-industrial levels. The Paris climate agreement in 2015 established the goal of keeping the increase in the global average temperature to no more than 2C and trying not to surpass 1.5C.
Temperature curve
Richard Black said from the non-profit organization the Energy and Climate Intelligence Unit: “Coming just before COP26, this report is a massive wake-up call to all those governments that have not yet put forward realistic plans to cut emissions over the next decade.
“It will show that choices made now have a big effect on our future – leading to a runaway world of wild weather impacts and incalculable risks at one end, and at the other a future where climate change is constrained within manageable bounds.”
So, what can we expect from the report?
According to many observers, science has significantly improved in the last few years. “Our models have gotten better, we have a better understanding of the physics and the chemistry and the biology, and so they’re able to simulate and project future temperature changes, and precipitation changes much better than they were,” said Dr. Stephen Cornelius from WWF, an observer at IPCC meetings.
“Another change has been that attribution sciences have increased vastly in the last few years. We can make greater links between climate change and extreme weather events.” As well as updates on temperature projections, there will likely be a strong focus on the question of humanity’s role in creating the climate crisis. In the last report in 2013, the IPCC said humans had been the “dominant cause” of global warming since the 1950s.
The message in the latest report is expected to be even more robust, with warnings of how soon global temperatures could rise 1.5C above pre-industrial levels. Experts say the impacts of climate change are far more severe when the increase is more significant than 1.5C.
One of the most important questions concerns sea-level rise. This has long been a controversial issue for the IPCC, with their previous projections scorned by some scientists as far too conservative. It is expected that this time the IPCC will also outline just how much of an influence humans are having on the oceans, the atmosphere, and other aspects of our planetary systems.
“In the past, they have been so reluctant to give a plausible upper limit on sea-level rise, and we hope they finally come around this time,” said Prof Arthur Petersen from UCL in London. As the world has experienced a series of devastating fires and floods in recent months that have been linked to climate change, the report will also include a new chapter relating extreme weather events to rising temperatures.
What is the IPCC?
The Intergovernmental Panel on Climate Change is a UN body set up in 1988 to assess the science around climate change. The IPCC provides governments with the scientific information they can use to develop policies on global heating.
The first of its comprehensive Assessment Reports on climate change was released in 1992. The sixth in this series will be split into four volumes, the first of which – covering the physical science behind climate change – will be published on Monday. Other parts of the review will cover impacts and solutions. A summary has been approved in a process involving scientists and representatives of 195 governments.
