Tuesday, June 25, 2024

IPCC’s Special Report on the Impact of Global Warming of 1.5°C

The report's full name is Global Warming of 1.5°C, an IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.

Main IPCC page:

The Report:

Summary for Policy Makers:

Headline Statements: 

In October 2018 the Intergovernmental Panel on Climate Change (IPCC) issued a special report on the impact of global warming of 1.5°C.  The report, which was the result of 3 years of research, says that going past 1.5°C would be highly detrimental to the planet’s liveability, and that at the current rate of global warming we could exceed a 1.5° increase in 12 years – by 2030.  The earth’s temperature has already increased by 1°C since pre-industrial times, and we are already seeing the effects of this in extreme weather patterns, rising sea levels and diminishing Arctic sea ice.  The report says that limiting global temperature increase to no more than 1.5°C is important, and shows that the effects of 2°C of further warming would be much more serious.

Who and what is at risk?

  • Coral Reefs:  Coral reefs would decline by 70-90% with global warming of 1.5°C, whereas virtually all would be lost at 2°C.
  • Sea-levels:  Global sea-levels will rise about 10cm (4in) more if we let warming go to 2°C. Keeping to 1.5°C would mean that 10 million fewer people would be exposed to the risks of flooding.  
  • Food Shortages:  Reductions in projected food availability are larger at 2ºC than at 1.5°C of global warming.  Limiting warming to 1.5°C compared with 2ºC is projected to result in smaller net reductions in yields of maize, rice, wheat, and potentially other cereal crops, particularly in sub-Saharan Africa, Southeast Asia, and Central and South America.
  • Livestock:  Livestock are projected to be adversely affected with rising temperatures, depending on the extent of changes in feed quality, spread of diseases, and water resource availability.
  • Water shortages:  Limiting global warming to 1.5°C compared to 2°C may reduce the proportion of the world’s population exposed to climate-change induced increase in water stress by up to 50%.
  • Ecosystems:  Limiting global warming to 1.5°C compared to 2°C is projected to lower the impacts on terrestrial, freshwater, and coastal ecosystems.  On land, impacts on biodiversity and ecosystems, including species loss and extinction, are projected to be lower at 1.5°C of global warming compared to 2°C. 
  • Economy:  There is higher economic growth at 1.5°C than there is at 2°C and you don’t have the higher risk of catastrophic impacts at 1.5° that you do at 2°.
  • Disadvantaged Populations:  These include small-island developing states, least developed countries, some indigenous peoples, and local communities dependent on agricultural or coastal livelihoods – and they are at high risk.  Small island and low-lying states in particular are at risk of being inundated with flooding.
Coral reefs could be completely wiped out

What needs to be done?

“The next few years are probably the most important in our history,” said Debra Roberts, Co-Chair of IPCC Working Group II.  “Limiting warming to 1.5°C is possible but would require unprecedented changes,” said Jim Skea, Co-Chair of IPCC Working Group III.  Some of the kinds of actions that would be needed to limit global warming to 1.5°C are already underway around the world, but they would need to accelerate. 

The following is a summary of the actions that need to be taken in order to limit the increase to no more than 1.5°C:

CO2 and Methane :  

– Massive reductions in the emissions of methane and black carbon (35% or more of both by 2050 relative to 2010).

– Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45% from 2010 levels by 2030, reaching ‘net zero’ around 2050.

– A shift away from fossil fuels by mid-century, with coal phased out far sooner than previously suggested.

– The report says that carbon may have to be sucked out of the air by machines and stored underground, and that these devices exist already.  “Frankly, the more we are prepared to make changes to behavioural patterns that reduce greenhouse gas emissions, the less we would need to rely later on more difficult options that we don’t yet fully understand like carbon dioxide removal,” said Prof. Jim Skea. 

Land use changes: Sustainable intensification of land use practices, ecosystem restoration and changes towards less resource-intensive diets.  Vast tracts of land given over to forests.

International Cooperation: International cooperation between and within countries and communities, without making the poor and disadvantaged worse off.

Transition to green and sustainable practises: Rapid and far-reaching transitions in land, energy, industry, buildings, transport, and cities.

Islands like the Maldives could be wiped out by rising sea levels

What actions can we take as individuals:

The report urges people to:

  • Buy less meat, milk, cheese and butter.
  • Buy more locally sourced seasonal food.
  • Throw less food away.
  • Drive electric cars but walk or cycle short distances.
  • Take trains and buses instead of planes.
  • Use videoconferencing instead of business travel.
  • Use a washing line instead of a tumble dryer.
  • Insulate homes.
  • Demand low carbon in every consumer product.

Lifestyle changes can make a big difference, said Dr. Debra Roberts.  “You might say you don’t have control over land use, but you do have control over what you eat and that determines land use.”

This is the final call, say scientists, the most extensive warning yet on the risks of rising global temperatures.  Keeping to the preferred target of 1.5°C above pre-industrial levels will mean “rapid, far-reaching and unprecedented changes in all aspects of society”.


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