Climate Change Set in Motion; Some Remain Irreversible; IPCC  

The world is at a pivotal moment in the fight to protect our planet, and the momentum is about to reach new heights. Leaders, industry giants, and experts from around the globe gathered for the Climate Ambition Summit on September 20. The stakes couldn't be higher, as nearly all environmental indicators are off-course or worsening. The consequences of climate change, from extreme weather displacing millions to escalating global temperatures and devastating wildfires, demand urgent action.

Climate change is widespread, rapid, and intensifying, and some trends and changes already set in motion such as continued sea level rise are irreversible over hundreds to thousands of years, according to the latest much-anticipated Intergovernmental Panel on Climate Change (IPCC) report, released on Monday.

The scientists observed that human induced climate change is already affecting many weather and climate extremes in every region across the globe. They mentioned that several of these changes are unprecedented, and some of the shifts are in motion now, while some – such as continued sea level rise – are already ‘irreversible’ for centuries to millennia,  ahead,  the report warns.

However, the IPCC pointed out that there was still time to limit climate change. The report said that strong and sustained reductions in emissions of carbon dioxide and other greenhouse gases, could quickly make air quality better, and in 20 to 30 years global temperatures could stabilize.


On the IPCC report, UN Secretary General António Guterres said that the report was nothing less than “a code red for humanity.”

“The alarm bells are deafening, and the evidence is irrefutable,” he said.

He pointed out that the internationally agreed threshold of 1.5 degrees above pre-industrial levels of global heating was “perilously close. “We are at imminent risk of hitting 1.5 degrees in the near term. The only way to prevent exceeding this threshold, is by urgently stepping up our efforts, and persuing the most ambitious path,” he said.

Pointing out that solutions were clear, the UN chief said that inclusive and green economies, prosperity, cleaner air and better health are possible for all, if the world respond to the crisis with solidarity and courage.

He mentioned that all nations, especially the advanced G20 economies – needed to join the net zero emissions coalition and reinforce their promises on slowing down and reversing global heating ahead of the crucial COP26 climate conference in Glasgow in November.

Meanwhile, IPCC Chair  Hoesung Lee said “this report reflects extraordinary efforts under exceptional circumstances. The innovations in this report, and advances in climate science that it reflects, provide an invaluable input into climate negotiations and decision-making.”


The report prepared by 234 scientists from 66 countries, provides new estimates of the chances of crossing the global warming level of 1.5°C in the next decades. It also says that limiting warming to close to 1.5°C or even 2°C will be beyond reach unless immediate, rapid and large-scale reductions in greenhouse gas emissions are adopted.

The IPCC report shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900. It also said that global temperature is expected to reach or exceed 1.5°C of warming over the next 20 years. They concluded this 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.

IPCC Working Group I Co-Chair Valérie Masson-Delmotte opined that the climate was changing and the role of human influence on the climate system was undisputed. Moreover, the scientist mentioned that the new report reflected major advances in the science of attribution – understanding the role of climate change in intensifying specific weather and climate events.

Noting that the report was a reality check, Masson-Delmotte said that world had a 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.”


The scientists report that climate changes will increase in all regions in the coming decades. 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, it said.

They also mentioned that climate change was bringing multiple different changes in different regions. These include changes to wetness and dryness, winds, snow and ice, coastal areas and oceans.

Some of the changes include;

  • Intensifying the water cycle. This brings more intense rainfall and associated flooding, as well as more intense drought in many regions.
  • Affecting rainfall patterns. In high latitudes, precipitation is likely to increase, while it is projected to decrease over large parts of the subtropics. Changes to monsoon precipitation are expected, which will vary by region.
  • Coastal areas will see continued sea level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion. Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century.
  • Further warming will amplify permafrost thawing, and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic sea ice.
  • Changes to the ocean, including warming, more frequent marine heatwaves, ocean acidification, and reduced oxygen levels have been clearly linked to human influence. These changes affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.
  • For cities, some aspects of climate change may be amplified, including heat (since urban areas are usually warmer than their surroundings), flooding from heavy precipitation events and sea level rise in coastal cities

The scientists underscore that 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 IPCC Working Group I Co-Chair Panmao Zhai.

The report explains that from a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative carbon dioxide emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions.

“Strong, rapid and sustained reductions in methane emissions would also limit the warming effect resulting from declining aerosol pollution”, the report said.


The IPCC is the UN body for assessing the science related to climate change. Established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988, it provides political leaders with periodic scientific assessments concerning climate change, its implications and risks, as well as to put forward adaptation and mitigation strategies.


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