United in Science 2021

No alternative left to ambitious climate action according to latest MWO report

No alternative

The United in Science 2021 report is published jointly by WMO and a few other organisations. According to the report, world’s greenhouse gas emission has bounced back to the same levels before the pandemic. The world is significantly off-schedule to meet the goals set by the Paris Agreement. UN Secretary-General Guterres says, there is no alternative if we are to achieve a safer, more sustainable and prosperous future for all.

Here are the key messages from the report.

Greenhouse Gas Concentrations in the Atmosphere

  • Concentrations of the major greenhouse gases – CO2, CH4, and 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 36.6 GtCO2 in 2019, followed by an extraordinary drop of 1.98 GtCO2 (5.6%) in 2020 due to the COVID-19 pandemic.
  • The drop in CO2 emissions is temporary, and based on preliminary estimates, from January–July 2021 global emissions in the power and industry sectors were already at the same level or higher than in the same period in 2019. Emissions from road transport remained about 5% lower.
  • Recent emissions trends of N2O, the third most important greenhouse gas after CO2 and CH4, exceed the most greenhouse gases intense socioeconomic pathways used to explore future climate change.

Global Climate in 2017-2021

  • The global average mean surface temperature for the period from 2017–2021 is among the warmest on record, estimated at 1.06 °C to 1.26 °C 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-caused climate change has been identified in the extraordinary North American extreme heat and west European floods.

Highlights of IPCC AR6: The Physical Science Basis

  • It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.
  • The scale of recent changes across the climate system as a whole and the present state of many aspects of the climate system are unprecedented over many centuries to many thousands of years.
  • Human-induced climate change is already increasing the frequency and intensity of many weather and climate extremes in every region across the globe.

Heatwaves, Wildfires, and Air Pollution: Compounding and Cascading Climate Hazards to Health

  • 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.
  • 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.

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 2 °C, global mean sea level would likely rise 0.3–0.6 m by 2100 and could rise by 0.3–3.1 m by 2300 (relative to 1995-2014).
  • If greenhouse emission continue to rise unabated global mean sea level will likely rise 0.6–1.0 by 2100 (relative to 1995- 2014) and, with less confidence, range from 1.7–6.8 m (perhaps more) by 2300 with further large rises continuing beyond.
  • Even with climate stabilization, 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.

Global Climate in 2021-2025

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

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 2 °C goal, and 32 GtCO2e lower for the 1.5 °C 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.

Read full report

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