Credit: WMO/ United in Science 2021

We are not growing back greener: United in Science 2021

The latest UN’s climate compilation report released late last week, has shown Covid-19 did not slow the relentless advance of climate change and there is no sign that “we are growing back greener”

The new report, United in Science 2021, which is the third in a series, has been released after the IPCC’s Sixth Assessment Report and provided similar key messages on climate change impacts; the scale of recent changes across the climate system as a whole is unprecedented over many centuries to many thousands of years and even with ambitious action to slow greenhouse gas emissions, sea levels will continue to rise and threaten low-lying islands and coastal populations throughout the world.

More critically, the report notes that CO2 emissions are rapidly recovering after “a temporary blip” due to the economic slowdown and are nowhere close to reduction targets.

GHG concentrations in the atmosphere, in addition, continue at record levels, committing the planet to dangerous future warming, according to the report with inputs from multi-agencies including the World Meteorological Organization (WMO), UNEP, WHO, IPCC, the Global Carbon Project (GCP), the World Climate Research Programme (WCRP) and the Met Office (UK).

The report notes that the rising global temperatures are fuelling devastating extreme weather throughout the world, with spiralling impacts on economies and societies. While the average global temperature for the past five years was among the highest on record, there is an increasing likelihood that temperatures will “temporarily breach” the threshold of 1.5 Celsius above the pre-industrial era in the next five years.

“Throughout the pandemic, we have heard that we must build back better to set humanity on a more sustainable path and to avoid the worst impacts of climate change on society and economies. This report shows that so far in 2021 we are not going in the right direction,” said WMO Secretary-General Prof. Petteri Taalas Taalas.

UN Secretary-General Antonio Guterres said this report by the United Nations and global scientific partner organizations provides a holistic assessment of the most recent climate science.

“The result is an alarming appraisal of just how far off course we are. We are still significantly off-schedule to meet the goals of the Paris Agreement,” said the UN chief.

The UN chief said unless there are immediate, rapid, and large-scale reductions in GHGs emissions, limiting warming to 1.5C will be impossible, with catastrophic consequences for people and the planet on which they depend.

Key takeaways

GHG concentrations in the atmosphere

  • Concentrations of the major greenhouse gases_ carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)_continued to increase in 2020 and the first half of 2021.
  • Overall emissions reductions in 2020 likely reduced the annual increase of the atmospheric concentrations of long-lived greenhouse gases, but this effect was too small to be distinguished from natural variability.
  • Reducing atmospheric methane (CH4) in the short term could support the achievement of the Paris Agreement. This does not reduce the need for strong, rapid and sustained reductions in CO2 and other greenhouse gases.

Global GHG emissions and budgets

  • Fossil CO2 emissions_coal, oil, gas and cement_peaked at 36.64 GtCO2 in 2019, followed by an extraordinary drop of 1.98 GtCO2 (5.6%) in 2020 due to the COVID-19 pandemic.
  • Based on preliminary estimates, global emissions in the power and industry sectors were already at the same level or higher in January-July 2021 than in the same period in 2019, before the pandemic, while emissions from road transport remained about 5% lower. Excluding aviation and sea transport, global emissions were at about the same levels as in 2019, averaged across those 7 months.
  • Recent emissions trends of N2O, the third most important greenhouse gas after CO2 and CH4, exceed the most greenhouse gases intense socio-economic pathways used to explore future climate change.

Emissions gap

  • Five years after the adoption of the Paris Agreement, the emissions gap is as large as ever; global emissions need to be 15 GtCO2e lower than current unconditional Nationally Determined Contributions (NDCs) imply for a 2C goal, and 32 GtCO2e lower for the 1.5C goal.
  • The COVID-19 crisis offers only a short-term reduction in global emissions. It will not significantly reduce emissions by 2030 unless countries pursue an economic recovery that incorporates strong decarbonization.
  • The increasing number of countries committing to net-zero emission goals is encouraging, with about 63% of global emissions now covered by such goals. However, to remain feasible and credible, these goals urgently need to be reflected in near-term policy and in significantly more ambitious NDCs for the period to 2030.

Global climate in 2017-2021

  • The global average mean surface temperature for the period from 2017-2021 based on data until July is among the warmest on record, being estimated at 1.06 to 1.26C above pre-industrial (1850–1900) levels.
  • In every year from 2017 to 2021, the Arctic average summer minimum and average winter maximum sea-ice extent were below the 1981-2010 long term average. In September 2020, the Arctic sea-ice extent reached its second lowest minimum on record.
  • 2021 recorded devastating extreme weather and climate events. A signature of human-induced climate change has been identified in the extraordinary North American extreme heat and west European floods.

Global climate in 2021-2025

  • Annual global mean near-surface temperature is likely to be at least 1C warmer than pre-industrial levels (defined as the 1850–1900 average) in each of the coming five years and is very likely to be within the range 0.9 to 1.8C.
  • There is a 40% chance that average global temperature in one of the next five years will be at least 1.5C warmer than pre-industrial levels but it is very unlikely (~10%) that the 5-year mean temperature for 2021-2025 will be 1.5C warmer than pre-industrial levels.
  • Over 2021-2025, high latitude regions and the Sahel are likely to be wetter than the recent past.

Compounding and cascading climate hazards to health

  • COVID-19 infections and climate hazards such as heatwaves, wildfires and poor air quality combine to threaten human health worldwide, putting vulnerable populations at particular risk.
  • COVID-19 recovery efforts should be aligned with national climate change and air quality strategies to reduce risks from compounding and cascading climate hazards, and gain health co-benefits.
  • Rising temperatures are linked to increased heat-related mortality and work impairment, with an excess of 103 billion potential work hours lost globally in 2019 compared with those lost in 2000.

Sea-level rise and coastal Impacts

  • Global mean sea levels rose 20 cm from 1900 to 2018 and at an accelerated rate of 3.7+0.5 mm/yr from 2006 to 2018.
  • Even if emissions are reduced to limit warming to well below 2C, global mean sea level would likely rise by 0.3-0.6 m by 2100, and could rise 0.3-3.1 m by 2300.
  • Adaptation to this residual rise will be essential. Adaptation strategies are needed where they do not exist, especially in low-lying coasts, small islands, deltas and coastal cities.

Sources: WMO/ United in Science 2021