A report by the Intergovernmental Panel on Climate Change (IPCC) of the United Nations has said that to avoid the damages from climate change, the world would require rapid, far reaching and unprecedented changes in all aspects of society.
A failure by countries to meet voluntary targets to limit global warming to ‘well below’ two degrees Celsius or 3.6 degrees Fahrenheit, would be devastating for some ecosystems and raise sea levels to flood many major cities and some entire countries, among other risks, the report says.
The new report titled, “Global Warming of 1.5°C” is 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.
The report was approved by the IPCC last Saturday and released yesterday in Incheon in South Korea. It will be a key scientific input for the Katowice Climate Change Conference in Poland in December this year, when governments review the Paris Agreement to tackle climate change.
“With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policy relevance of the IPCC,” said IPCC chair Hoesung Lee.
Ninety-one authors and review editors from 40 countries prepared the IPCC report in response to an invitation from the United Nations Framework Convention on Climate Change when it adopted the Paris Agreement in 2015.
Keep warming at less than 1.5°C
“One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes,” said IPCC co-chair Panmao Zhai.
The report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C.
The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C , compared with at least once per decade with 2°C. Coral reefs would decline by 70%-90% with global warming of 1.5°C, whereas virtually all (> 99%) would be lost with 2°C.
“Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,” said IPCC Working Group II co-chair Hans-Otto Portner.
Limiting global warming would also give people and ecosystems more room to adapt and remain below relevant risk thresholds, added Mr Portner. The report also examines pathways available to limit warming to 1.5°C, what it would take to achieve them and what the consequences could be.
Some steps are already underway
“The good news is that 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,” said Working Group I co-chair Valerie Masson-Delmotte.
The report finds that limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities.
Carbon dioxide levels should reach ‘net zero’ by 2050
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. This means that any remaining emissions would need to be balanced by removing CO2 from the air.
“Limiting warming to 1.5°C is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said IPCC Working Group III co-chair Jim Skea.
“Limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on ecosystems, human health and well-being, making it easier to achieve the United Nations Sustainable Development Goals,” said IPCC Working Group III co-chair Priyardarshi Shukla.
It’s a political question
A press report in Wall Street Journal quotes World Wildlife Fund senior vice president for climate change and energy, Lou Leonard commenting on the IPCC report, “The reality is that the technology is there, we do know what to do, but will we? That’s a political question, not a technical question.”
The IPCC is the leading world body for assessing the science related to climate change, its impacts and potential future risks, and possible response options.