Emphasizing human actions still have the potential to determine the future course of climate by reducing green house gas emission, the scientists have concluded if proper steps are taken, it would not only limit the climate change, but also within three decades global temperatures would stabilize.
“This is the year countries must commit to deeper global greenhouse gas emissions cuts in time for the UN Climate Change Conference (COP26) in November. It’s the year in which we need to grow the global coalition of governments, companies, and organizations committed to achieving net-zero emissions by mid-century,” António Guterres, Secretary-General of the United Nations, stated on Monday, after releasing first part of Intergovernmental Panel on Climate Change (IPCC) working group’s Sixth Assessment Report.
The report released in Geneva provides the latest physical understanding of the climate system and climate change, bringing together findings on climate science based on 14,000 scientific studies.
The report underlines that “changes in the Earth’s climate are visible in every region and across the whole climate system”.
“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,” said Hoesung Lee, Chair of IPCC, during the online release of the report.
While strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases would limit climate change and quickly ensure benefits through improvement in air quality, it could take 20-30 years to see global temperatures stabilize, mentioned the report.
Titled ‘Climate Change 2021: the Physical Science Basis’, the report has been prepared by 234 authors from 65 countries. It carries regional information to help policy makers in taking steps to mitigate the adverse impact of climate change. The newly developed Interactive Atlas (interactive-atlas.ipcc.ch) allows countries to make informed decisions.
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.
Currently, higher than desired levels are believed to be the cause of unprecedented warm weather in many parts of the globe besides hurricanes and other unusual weather fluctuations.
Reiterating the findings of the first IPCC report 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, warming over land is larger than the global average, and it is more than twice as high in the Arctic.
“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” stated IPCC Working Group I Co-Chair Panmao Zhai.
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. 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.
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.
“It has been clear for decades that the Earth’s climate is changing, and the role of human influence on the climate system is undisputed,” stressed Masson-Delmotte. The new report also points to 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 strives to emphasize that human actions still have the potential to determine the future course of climate. The evidence is clear that carbon dioxide (CO2) is the main driver of climate change, even as other greenhouse gases and air pollutants also affect the climate.
“Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate,” said Zhai