‘Human influence cause of 
runaway climate warming’

Slug: 2021 is one of seven warmest years: WMO

Dr Abhijeet Chauhn

Earth is a unique planet. It is the only one in the solar system that has both an atmosphere and oceans, and these have created ideal conditions for life to evolve and flourish. Currents in the atmosphere and oceans carry heat and moisture around the globe, so life can exist almost everywhere. These currents also create the weather.

This changes daily, but in predictable patterns. The pattern of weather in a particular place is its climate. Climates vary slowly over time, forcing life to adapt to new conditions, but recently the rate of climate change has sped up. Temperature is just one of the indicators of climate change. Others include greenhouse gas concentrations, ocean heat content, ocean pH, global mean sea level, glacial mass and sea ice extent.

For most of human history, the world’s climates have been unusually stable, enabling civilizations to rise and prosper. But climates are changing, polar ice is melting, temperate regions are suffering more heatwaves and severe storms, and tropics seem to be getting drier.

Global average temperatures started rising in about 1900. They have risen and fallen many times since then, but the trend has crept upward – slowly at first, but more rapidly since the 1970s. The temperature rise roughly matches the rise of modern industry, the growth of huge cities, increasing quantities of fuel such as coal and oil that we burn to provide energy for heating, electrical power and transportation.

In 1890s, Swedish chemist Svante Arrhenius concluded that past ice ages might have been caused by fewer volcanic eruptions pumping gases such as CO2 into the atmosphere. He realised that intense industrial activity and burning fuels such as coal would make the world warm-up, thus discovering the factor that linked industrialization and fuel use with changing global temperatures.

Climate change is widespread and intensifying while some trends are now irreversible, as per the Intergovernmental Panel on Climate Change (IPCC) report released in 2021. The report – titled ‘Climate Change 2021: The Physical Science’ – is the sixth since IPCC was constituted in 1988. It is aimed at providing a scientific analysis of global climate change for policymakers around the world.

The Union government welcomed this global climate change assessment report in August last year. Several Indian scientists participated in it, which says that the world is dangerously close to runaway warming for which humans are “unequivocally” to blame. An observation in the report about India is that of monsoon patterns in South Asia. Rising temperature will lead to increased frequency and intensity of extreme events including heat waves and heavy rainfall.

The United Nations Secretary-General Antonio Guterres, in his tweet last year, said, “Alarm bells in the working group’s report are deafening and the evidence is irrefutable.” He noted that the internationally-agreed threshold of 1.5 degrees above pre-industrial levels of global heating was “perilously close.” On 21 January, 2022 – in his remarks to the General Assembly on his priorities this year – the Secretary-General said, “The battle to keep the 1.5-degree goal alive will be won or lost in this decade.”

This report cites that human influence has warmed climate at a rate that is unprecedented in the last 2,000 years. The document shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming in 1850-1900. Averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of heating.

IPCC scientists warn global warming of 2°C will be exceeded during the 21st century. Unless rapid and deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades, achieving the goals of the Paris Agreement-2015 “will be beyond reach”.

Experts also point out that evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, tropical cyclones, and their attribution to human influence, has strengthened. The report makes clear that while natural drivers will modulate human-caused changes, especially at regional levels and in the near term, they will have little effect on long-term global warming.

Meanwhile, data released by the World Meteorological Organization (WMO) shows that 2021 was one of the seven warmest years on record. Although average global temperatures were temporarily cooled by the 2020-2022 La Niña events, 2021 was still one of the seven warmest years on record, according to six leading international datasets consolidated by WMO.

These six international datasets ensure the most comprehensive, authoritative temperature assessment. The same data, in its annual state, are used for climate reports that inform the international community about global climate indicators. 2021 is the seventh consecutive year (2015-2021) where the global temperature has been over 1°C above pre-industrial levels, according to all WMO datasets.

Global warming and other long-term climate change trends are expected to continue as a result of record levels of heat-trapping greenhouse gases in the atmosphere. Scientists point out that ‘El Niño’ and ‘La Niña’ are climate patterns in the Pacific Ocean that can affect weather worldwide. 

Since the 1980s, each decade has been warmer than the previous one. This is expected to continue. The warmest seven years have all been since 2015, with 2016, 2019 and 2020 constituting the top three. An exceptionally strong El Niño event occurred in 2016, which contributed to record global average warming.

As far as climatic extremes are concerned, 2021 will go down in history for different parts of the world recorded varied extreme conditions. While Canada recorded a high of almost 50°C (comparable to the conditions in the Sahara desert), extreme flooding rampaged parts of Asia and Europe while several regions in Africa and Latin America experienced severe drought.

(The writer has been selected for PMO Projects-NSB Media Fellowship-2022).