Kampala, Uganda | Ronald Musoke | Scientists are observing changes in the Earth’s climate in every region and across the whole climate system, according to the latest Intergovernmental Panel on Climate Change (IPCC) Report, released Aug.09.
“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” said IPCC Working Group I Co-Chair Panmao Zhai.
“Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO 2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate.”
The report which has been published three months ahead of the next round of climate change negotiations summit in Glasgow, Scotland, notes that there is “now unequivocal evidence that humans are to blame for increasing temperatures.”
Prof. Ed Hawkins, from the University of Reading, UK, and one of the report’s authors told the BBC that the scientists cannot be any clearer on this point. “It’s a statement of fact, we cannot be any certain, it is unequivocal and indisputable that humans are warming the planet.”
Petter Taalas, the Secretary General of the World Meteorological Organization used sports terminology to describe what the world is currently experiencing. “One could say the atmosphere has been exposed to doping, which means we have begun observing extremes more often than before,” he told the BBC.
For the first time, the IPCC’s sixth Assessment Report provides a more detailed regional assessment of climate change, including a focus on useful information that can inform risk assessment, adaptation, and other decision-making.
It also provides a new framework that helps translate physical changes in the climate – heat, cold, rain, drought, snow, wind, coastal flooding and more – into what these phenomena mean for society and ecosystems.
The publication is the latest set of IPCC reports that assess the scientific knowledge on climate change including the world’s past, present and future climate, its impact and future risks and options for adaptation and mitigation.
“This report reflects extraordinary efforts under exceptional circumstances,” said Hoesung Lee, the Chair of the IPCC—the international body assessing the science related to climate change, in a press statement.
“The innovations in this report, and advances in climate science that it reflects, provide an invaluable input into climate negotiations and decision-making.”
Commenting about the report, Antonio Guterres, the UN Secretary General noted that the world can only avert a climate catastrophe if “we combine forces now.” “But, as today’s report makes clear, there is no time for delay and no room for excuses. I count on government leaders and all stakeholders to ensure COP26 is a success.”
Boris Johnson, the UK Prime Minister who will be hosting COP26 noted that the report “makes for sobering reading,” adding that, “It is clear that the next decade is going to be pivotal to securing the future of our planet.”
“We know what must be done to limit global warming—consign coal to history and shift to clear energy sources, protect nature and provide climate finance for countries on the frontlines,” he said.
The authors say that since 1970, global surface temperatures have risen faster than in any other 50-year period over the past 2,000 years. This warming is already affecting many weather and climate extremes in every region across the globe.”
The new report also makes clear that the warming people have experienced to date has made changes to many of the planetary support systems that are irreversible on time scales of centuries to millennia.
Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion—such as continued sea level rise—are irreversible over hundreds to thousands of years. But, strong and sustained reductions in emissions of carbon dioxide (CO 2 ) and other greenhouse gases would limit climate change.
While benefits for air quality would come quickly, it could take 20-30 years to see global temperatures stabilize, according to the IPCC Working Group I report, Climate Change 2021: the Physical Science Basis, approved on Aug.06 by 195 member governments of the IPCC, through a virtual approval session that was held over two weeks starting on July 26.
The report provides new estimates of the chances of crossing the global warming level of 1.5°C in the next decades, and finds that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5°C or even 2°C will be beyond reach.
The report shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900, and finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of warming.
This assessment is based on improved observational datasets to assess historical warming, as well progress in scientific understanding of the response of the climate system to human-caused greenhouse gas emissions.
“This report is a reality check,” said IPCC Working Group I Co-Chair Valérie Masson-Delmotte, “We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare.”
Many characteristics of climate change directly depend on the level of global warming, but what people experience is often very different to the global average. For example, the report noted, warming over land is larger than the global average, and it is more than twice as high in the Arctic.
Yet the new report also reflects major advances in the science of attribution – understanding the role of climate change in intensifying specific weather and climate events such as extreme heat waves and heavy rainfall events.
The report also shows that human actions still have the potential to determine the future course of climate. The evidence is clear that carbon dioxide (CO 2 ) is the main driver of climate change, even as other greenhouse gases and air pollutants also affect the climate.
The report projects that in the coming decades, climate changes will increase in all regions. For 1.5°C of global warming, there will be increasing heat waves, longer warm seasons and shorter cold seasons while, at 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report shows.
But it is not just about temperature, the scientists said. Climate change is bringing multiple different changes in different regions – which will all increase with further warming. These include changes to wetness and dryness, to winds, snow and ice, coastal areas and oceans.
The IPCC was set up in 1988 by the World Meteorological Organization and the United Nations Environment Programme (UNEP) to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks and options for adaptation and mitigation.