1.5C of global warming projected over next 20 years: IPCC

The latest report to assess the status of the world’s climate and related conditions by the Intergovernmental Panel on Climate Change (IPCC) has projected that the global warming threshold set by the world’s community, 1.5C, could be in reach much earlier than expected, with “unequivocal” scientific voices that human influence has warmed the climate with unprecedented or even irreversible effects in centuries or thousands of years

The global climate assessing body, IPCC, has launched its Working Group I’s report, “Climate Change 2021: the Physical Science Basis”, which is part of its periodical Sixth Assessment Report or AR6. The report was prepared by 234 scientists from 66 countries and approved by 195 member governments of the IPCC through a virtual approval session that was held over two weeks starting on July 26 before finishing on Friday.

This comes ahead of the coming climate conference, COP 26, scheduled at the end of this year and seen as the deadline for the international community to take drastic cuts on Greenhouse Gases (GHGs) Emissions or face several irreversible catastrophes in the coming decades.

According to the report, human activities have caused GHGs emissions that are responsible for approximately 1.1C of warming since 1850-1900. It also finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5C of warming.

“Unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5C or even 2C will be beyond reach,” the report notes.

Such global temperature rise is unprecedented in at least the last 2,000 years, according to the report. The report has also found that in 2019, CO2 concentrations in the atmosphere were higher than at any time in at least 2 million years, and concentrations of methane and nitrous oxide were higher than at any time in the last 800,000 years. Global mean sea level, in the meantime, has risen faster since 1900, than over any preceding century in at least the last 3,000 years.

IPCC Working Group I Co-Chair Panmao Zhai said of the consequences; “Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming.”

The report projects that in the coming decades, climate changes will increase in all regions. For 1.5C of global warming, there will be increasing heat waves, longer warm seasons, and shorter cold seasons. At 2C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health.

Aside from temperature, multiple different changes will occur in different regions, which will all increase with further warming. These include changes to wetness and dryness, winds, snow and ice, coastal areas and oceans.

Some notable changes are as follows;

*More intense rainfall and associated flooding, as well as more intense drought in many regions.

*Change in 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.

*Cities’ environment and micro-climate may be amplified, including heat, flooding from heavy precipitation events, and sea-level rise in coastal cities.

(Read: Common regional changes: Asia)

“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.

Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net-zero CO2 emissions, Dr. Zhai added.

I Credit: IPCC

“Code red for humanity”

The UN Secretary-General António Guterres said the Working Group’s report was nothing less than “a code red for humanity”. The alarm bells are deafening, and the evidence is “irrefutable”, he said.

He further noted 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 pursuing the most ambitious path.

“We must act decisively now, to keep 1.5 alive,” said the UN Secretary-General.

The UN chief added that ahead of the COP26 climate conference in Glasgow in November, 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, “with credible, concrete, and enhanced Nationally Determined Contributions (NDCs)” that layout detailed steps.

“Inclusive and green economies, prosperity, cleaner air, and better health are possible for all if we respond to this crisis with solidarity and courage,” he said.

The Paris Agreement

The UN Climate Change or UNFCCC said the Working Group I’s report confirms that it is indisputable that human influence has warmed the climate system, raising the global surface temperature.

“The report provides an update on the physical science basis of climate change and confirms that there is no going back from some changes that are already affecting the climate system,” the UN climate body noted upon learning the launch of the report.

The body said the report has provided “an atlas” of regional observed and future impacts, which will allow policymakers and all other stakeholders to better inform climate policies at the regional and local levels.

It also helps identify the level of future emissions that will determine the level of future temperature rise and the severity of future climate change and the associated impacts and risks. Not only have CO2 concentrations increased in the Earth’s atmosphere, but the rate of the increase has also sped up, the UN climate body pointed.

“This assessment of the latest science is a severe warning regarding the well-being of human society and all life on Earth. It is testimony to the fact that efforts to reduce greenhouse gas emissions over the past decades have been wholly insufficient,” the UNFCCC remarked.

The UN climate body said 2021 marks a crucial year as nations submit their new or updated Nationally Determined Contributions (NDCs), embodying the efforts and actions of each country to respond to climate change and reduce emissions.

However, an initial synthesis of submitted new or updated NDCs early in 2021 showed that collective efforts fall far short of what is required by science to limit global temperature increases by the end of the century to 2C, let alone the desired objective of less than 1.5C, said the organization.  

At present, only slightly more than half of all Parties to the Paris Agreement have submitted new or updated NDCs, the UNFCCC noted. As of July 31, the UNFCCC secretariat received new or updated NDCs from 110 Parties or 58%. The set goal is by the end of this decade emissions must have been reduced by at least 45% compared to 2010 levels.

“Given the latest assessment of the physical science basis of climate change, accepting and rising to the challenge of increasing ambition needs to be the way forward. Pursuing efforts towards 1.5C through the implementation of ambitious NDCs is essential for our future and future generations’ well-being,” the UNFCCC said.

The World Meteorological Organization, meanwhile, said it is essential to pay attention to climate adaptation, apart from the urgent need for climate mitigation.

WMO chief, Peteri Taalas said since the negative trend in climate will continue for decades and in some cases for thousands of years, one powerful way to adapt is to invest in early warning, climate and water services. So far, only half of the 193 members of WMO have such services in place, which means more human and economic losses, he said.

Climate Change 2021: The Physical Science Basis (SPM)

IPCC WGI Interactive Atlas

Sources: IPCC, UN News, UNFCCC