Climate change: Five lessons learned from the IPCC Report by Matt McGrath
Environment correspondent Published 1 Hour Ago
image source Copernicus/Sentinel-2 image caption Satellite images of wildfires in Evia, Greece
The UN report on climate change science is expected to have a significant impact. Matt McGrath, our environment correspondent, examines some of the most important lessons.
Climate change is rapid, widespread and intensifying. It's up to us.
The dangers of warming the planet for those living in the West are not something that is distant. They have an impact on people all over the world.
"Climate Change is not a problem of tomorrow, it's here and right now, and it affects every region of the world," stated Dr Friederike Otto, a professor at Oxford and one of many authors on UN's Intergovernmental Panel on Climate Change's (IPCC) report.
This new publication is only as strong because of the scientific assertions it makes.
In the nearly 40 pages of the Summary for Policymakers, the phrase "very likely” appears 42 times. This is 90-100% certainty that something is true, according to scientific terms.
Professor Arthur Petersen from University College London (UCL) stated that "I don't think there's one kind of surprise that comes out. It's the overarching solidness which makes this the strongest IPCC Report ever made."
Professor Petersen, a former representative of the Dutch government at the IPCC was present at the approval session that produced the report.
"It's understated and it's cool. It's not accusing. It's bang bang bang bang. One clear point after another.
These points are most important because they show the humanity's responsibility for climate change.
There is no equivocating, it's us.
1.5C is the temperature limit for life support
The idea that 1.5C was the safe global limit of warming was not even considered when the IPCC's last report on climate change science was published in 2013.
However, in 2015's political negotiations for the Paris climate agreement, many island states and developing countries pushed for a lower temperature limit. They argued that this was necessary for their survival.
An 2018 special report on 1.5C showed that staying below the limit was much more beneficial than living in a 2C world. To get there, carbon emissions must be reduced by half by 2030, and net zero emissions by 2050. The limit would not be met if carbon emissions were cut in half by 2030 and 2052.
This finding is reaffirmed by the new report. In all scenarios, the threshold will be reached by 2040. 1.5C could disappear in a decade if emissions aren’t controlled.
Image source WaterAid/ Dennis Lupenga caption: Abandoned canoes found on cracked and dried-up shores of Lake Chilwa in Malawi
Net zero refers to reducing greenhouse gas emissions to the greatest extent possible by using clean technology and then absorption of any remaining gases through, for instance, tree planting.
Although the situation is grave, it's not an immediate calamity.
"The 1.5C threshold is a significant threshold politically, ofcourse, but it is not an edge from a climate point of view - that once you go above 1.5C, everything will suddenly become very catastrophic," said Dr Amanda Maycock from the University of Leeds and one of the authors of this new report.
"The lowest emission scenario we have evaluated in this report shows that global warming does stabilize around or below 1.5C later in the century. This would ensure that the impact of the climate change would be avoided.
The bad news is that the seas will continue rising regardless of what we do.
The IPCC was criticised in the past for being too cautious when it came down to assessing the risks of sea-level rising. Previous reports did not include the potential effects of melting of the Greenland or Antarctic ice sheets due to a lack of research.
This is not the time.
According to the report, sea levels could rise to more than the probable range under current scenarios. They could reach 2m by 2025 and 5m by 2050, respectively. These are not likely figures but they cannot be ruled out in the face of very high greenhouse gas emissions.
It's terrible enough. But even if we reduce emissions and keep the temperature at 1.5C by 2100 the waters will continue rising well into the future.
"The gorilla that stands tall in the background are these very frightening sea-level rise numbers over the long term," stated Prof Malte Meinshausen, a professor at the University of Melbourne who is also an IPCC author.
"The paper shows that even with 1.5C global warming, we can expect a long-term rise of 2 to 3 metres. Under the most extreme scenarios, we could see a multi-metre rise in sea level by 2150. This is scary because although it may not be at the end our lives, it is coming soon and will leave a huge legacy on this planet.
Even though the sea-level rise may be relatively minor, there will be knock-on effects we can't avoid.
"With gradual sea level rise, extreme sea-level event that occurred in the past, only once per century in the future, will occur more often in the future," stated Valrie Masson Delmotte, cochair of the IPCC working party that prepared the new report.
"Those that have occurred once in a century are likely to happen once or twice a decade by the middle of the next century." This report contains important information that you should consider and use to prepare for these events.
Good news: Scientists know more about how it will work
Although the warnings are more severe and clearer, there is still some hope in this report.
Scientists have been concerned for a long time that carbon dioxide could make the climate more sensitive than they believed.
To capture the potential warming that could result from doubling CO2 levels, they use the phrase equilibrium climate sensitivity.
Image source: Reuters caption A camera infrared captures methane escaping a natural gas facility
The last report showed that this was between 1.5C and 4.5C in 2013, with no best estimate.
The range is narrower this time and the authors choose 3C as the most likely figure.
What is the point?
Professor Piers Forster, University of Leeds, said that "we are now able constrain that with good degree of certainty" and that he used that to make much more precise predictions. He was also an author of the report.
"So, this way, we know net zero will actually deliver."
The report also includes a surprising mention of methane as a warming gas.
According to the IPCC around 0.3C of 1.1C world-wide warming due to methane comes from it.
In the short-term, reducing emissions from the oil and natural gas industry, agriculture, and rice cultivation could prove to be a huge win.
Fred Krupp from the US Environmental Defense Fund stated that the report "quashed any remaining debate about how urgent it is to reduce methane pollution, particularly from oil and gas sectors, where the available reductions can be made quickly and cheaply."
"When it comes down to our planet's overheating, every degree counts - and there is no quicker, more achievable, way to slow the rate at which we are warming than to reduce human-caused methane emission."
Politicians will be anxious, the courts will be busy
This report's timing, which comes just a few months before the crucial COP26 climate conference at Glasgow, suggests that it will be the foundation of negotiations. This report is in some way a part of the IPCC's previous assessments from 2013 and 2014. These assessments paved the path for the Paris climate accord.
This new study is stronger, clearer, and more certain about what will happen to politicians if they don't act.
If they fail to act quickly and COP26 ends with a disappointing fudge, the courts may become more involved.
Environmental campaigners in Ireland and the Netherlands have been able to successfully take the law to get governments and companies to address climate change science.
"We won't let this report go unanswered by inaction. Kaisa Kosonen (senior political advisor at Greenpeace Nordic) stated that instead, they will be taking the report to court.
"The IPCC strengthened the scientific evidence linking human emissions to extreme weather and has given everyone a powerful tool to hold governments and fossil fuel industries directly responsible for the climate emergency.
"One need only look at the recent victory of NGOs against Shell to see how powerful IPCC science is."