Climate Change

NDC compliance not enough, world may still be 2.5°C warmer by 2100: Study

IPCC reports also have limited coverage of temperature rise of 3°C or higher

By Rohini Krishnamurthy
Published: Monday 01 August 2022

NDCs, which countries agreed as part of the Paris Agreement, will not be enough to arrest global warming, according to a new research. In fact, Earth can still be hotter by 2.4 degrees Celsius in 2100.

The global community also need to prepare for even further rises in temperature, warned researchers who published the report in Proceedings of the National Academy of Sciences (PNAS) August 2, 2022.

The Intergovernmental Panel on Climate Change reports also have limited coverage of temperature rise of 3°C or higher, the authors of the paper noted.

The focus has been mainly on lower-end risks such as 1.5°C or 2°C warming, according to the report.

“We lack studies of plausible higher-end warming scenarios as well as how climate impacts can cause disastrous knock-on effects,” Luke Kemp, University of Cambridge’s Centre for the Study of Existential Risk and lead author of the study, told Down To Earth.

The authors of the report are from the University of Cambridge, Potsdam Institute for Climate Impact Research, University of Washington, Future of Humanity Institute at the University of Oxford, Washington State University, Wageningen University and Research, Nanjing University, Australian National University, Climate Change Institute and the University of Exeter.

The researchers believe that analysing catastrophic climate scenarios can help prevent them while also building societal resilience. Some argue that discussing extreme risks will dissuade people from action on climate change. But, Kemp and his colleagues disagree.

“What we need is honest and strategic communication about climate change. This includes picking the right messenger and frame. We should not make it an ideological issue,” he explained.

Climate change can trigger famine and undernutrition, extreme weather events, conflicts and vector-borne diseases and can topple the global food supply by disrupting the world’s most agriculturally productive areas, the report said.

As bad as it gets

Understanding the worst-case scenario is important because the current trajectory can raise temperatures to between 2.1°C and 3.9°C by 2100, the report highlighted.

Climate models currently in the news do not consider important factors such as the release of methane and carbon dioxide from the thawing of the Arctic permafrost and the carbon loss due to intense droughts and fires in the Amazon forest, according to the experts.

More research is needed in these areas. The report suggested that a warming of 3°C or more by the end of the century is a marker for extreme climate change.

The experts define global catastrophic risk as the probability of losing 25 per cent of the population worldwide and the severe disruption of food and other global critical systems within years or decades.

A global decimation risk is a probability of losing 10 per cent or more of the global population and the severe disruption of food and other global critical systems within years or decades, they added.

According to the 2021 Fragile State Index (FSI) cited in the PNAS report, India is vulnerable to climate risks. FSI is an annual report published by the United States think tank the Fund for Peace and the American magazine Foreign Policy.

India scored 77 points and was placed under the elevated warning level. The scoreboard ranges from 10 to 120, with ten given to sustainable nations and 120 to those under alert.

The researchers have charted a proposal for addressing the concerns highlighted in the report. These include:

  • Understanding extreme climate change dynamics and impacts in the long term
  • Exploring pathways to mass morbidity and mortality triggered by climate
  • Investigating social fragilities such as vulnerabilities, risk cascades and risk responses
  • Synthesising the research findings into integrated catastrophe assessments.

The researchers said countries would have to evaluate the indirect impacts of climate change as they are understudied.

“There is a need for an interdisciplinary endeavour to understand how climate change can trigger human mass morbidity and mortality,” co-author Kristie Ebi from the University of Washington said in a statement.

We need interventions to reduce the likelihood of conflicts, such as — nuclear disarmament, banning the development of new dangerous weapons such as lethal autonomous weapons and support for adaptation in vulnerable countries and international diplomacy, he added.

The immediate focus should be on slashing emissions, according to the expert.

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