Code red for humanity: UN report delivers dire warning on climate change

'CODE RED': IPCC says planet to warm by 1.5 degree Celsius in all growth scenarios over 20 yrs

Extreme climate occurrences in the form of heat waves, droughts, floods and thinning of glaciers are now indisputably linked to human behaviour and not natural causes, says the latest assessment report by global climate scientists, adding that some of these climate changes might be irreversible. The report, “Climate Change 2021”, from the United Nations’ Intergovernmental Panel on Climate Change (IPCC) also says the recent climate extremes are unprecedented in thousands of years.

The IPCC, in its Sixth Assessment Report (AR6), estimates that under all growth scenarios, the planet’s warming level will touch 1.5 degree Celsius. The report shows that emissions of greenhouse gases (GHGs) from human activities are responsible for approximately 1.1 degree Celsius of warming since 1850-1900. Averaged over the next 20 years, global temperature is expected to reach or exceed 1.5 degree Celsius above normal range, it says. UN Secretary-General António Guterres described the report as “a code red for humanity.”

The Climate Change 2021 report has been prepared by Working Group-I of the three groups formed for preparing the AR6. This is the first instalment of a report on a ‘physical science’ basis. The IPCC report comes ahead of the UN Climate Change conference (COP26) at Glasgow in November. At the last climate conference in Paris in 2015, 195 countries had adopted the agreement to keep global warming below 2 degrees Celsius, and preferably below 1.5 degrees Celsius.

A global warming level of 1.5 degrees Celsius would mean increased and more intense heat waves, longer summers and shorter winters. This, in turn, would impact the water cycle, and thereby the rains, glacier melting and sea levels.

The report noted that human-induced climate change is already affecting many weather conditions in every region across the globe. The evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, tropical cyclones, and their attribution to human influence has strengthened since AR5 (published in 2014)

“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,” said IPCC Working Group I Co-Chair Valérie Masson-Delmotte. “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 surface of Indian Ocean has warmed faster than the global average, said the report with “very high confidence”. Coastal areas of the Indian sub-continent stand at the risk of climate-related mishaps with rising water levels. Rising carbon dioxide levels have also increased the acidification of oceans, globally.

The report adds, again with “high confidence”, that warming has occurred in the Himalayas (along with the Swiss Alps and the Central Andes) and has increased with altitude. Such elevation-dependent warming could lead to faster changes in the snowline, the glacier equilibrium-line altitude and the snow/rain transition height, it says.

“Given that India is one of the most climate-vulnerable countries, we must recognise that even geographically faraway climatic changes can have consequences for our monsoons and intensity of extreme events,” said Arunabha Ghosh, CEO, Council on Energy, Environment and Water (CEEW).

The report indicated that CO2 is the main driver of climate change, leading the pack among other greenhouse gases and air pollutants.

Sunita Narain, director general, Centre for Science & Environment, said, "Technically, India is the third-highest annual carbon dioxide polluter in the world. But the scale of our contribution is so insignificant that it cannot be compared." However, she added, this should not take away from the fact that it's in the best interest of India to take steps to combat climate change – "at speed and at scale."

IPCC Working Group I Co-Chair Panmao Zhai added, “Stabilising the climate will require strong, rapid and sustained reduction 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.”

Ghosh said the business-as-usual development scenario would not work anymore. “Our focus should be on building climate-resilient physical and digital infrastructure along with inculcating social and behavioural changes in citizens and communities,” he said, adding that the international community should capitalise a Global Resilience Reserve Fund to help lower the peaks of climate risks for the most vulnerable countries.

EARTH ALERT

Human behaviour causing irreparable damage

• CO2 concentration highest in 2 million years
• Sea levels witnessing fastest rate of increase in 3,000 years
• Arctic sea ice at lowest level in 1,000 years (down 40% since 1979)
• Glaciers retreat unprecedented in 2,000 years
• Decrease in spring snow cover highest since 1950

Humans main drivers of

• Extreme heat, which is more frequent and intense
• Heavy rainfall – more frequent and intense
• Drought – increase in some regions
• Greater frequency of fire weathers
• Warming and acidifying of oceans, as they lose oxygen, highest since 1970s