Rapid
response needed to limit global warming
Intergovernmental
Panel on Climate Change
Limiting
global warming to 1.5°C would require rapid, far-reaching and unprecedented
changes in all aspects of society, the IPCC said in a new assessment. With clear benefits to people and natural ecosystems, limiting global warming to 1.5°C compared to 2°C could go hand in hand with ensuring a more sustainable and equitable society, the Intergovernmental Panel on Climate Change (IPCC) said on October 8.
The Special
Report on Global Warming of 1.5°C was approved by the IPCC on Saturday in
Incheon, Republic of Korea.
It will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.
It will be a key scientific input into the Katowice Climate Change Conference in Poland in December, 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 Hoesung
Lee, Chair of the IPCC.
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| The new normal |
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.
"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 Panmao Zhai, Co-Chair of IPCC Working Group I.
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 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost 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 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) 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 Hans-Otto Pörtner, Co-Chair of IPCC Working
Group II.
Limiting global
warming would also give people and ecosystems more room to adapt and remain
below relevant risk thresholds, added Pörtner.
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.
"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 Valerie Masson-Delmotte, Co-Chair of Working Group I.
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.
"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 Valerie Masson-Delmotte, Co-Chair of Working Group I.
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.
Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent 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.
Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent 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 Jim Skea, Co-Chair of IPCC
Working Group III.
Allowing the
global temperature to temporarily exceed or 'overshoot' 1.5°C would mean a
greater reliance on techniques that remove CO2 from the air to
return global temperature to below 1.5°C by 2100.
The effectiveness of such techniques are unproven at large scale and some may carry significant risks for sustainable development, the report notes.
The effectiveness of such techniques are unproven at large scale and some may carry significant risks for sustainable development, the report notes.
"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 Priyardarshi Shukla, Co-Chair
of IPCC Working Group III.
The decisions we
make today are critical in ensuring a safe and sustainable world for everyone,
both now and in the future, said Debra Roberts, Co-Chair of IPCC Working Group
II.
"This
report gives policymakers and practitioners the information they need to make
decisions that tackle climate change while considering local context and
people's needs. The next few years are probably the most important in our
history," she said.
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.
The report was
prepared under the scientific leadership of all three IPCC working groups.
Working Group I assesses the physical science basis of climate change; Working
Group II addresses impacts, adaptation and vulnerability; and Working Group III
deals with the mitigation of climate change.
The Paris
Agreement adopted by 195 nations at the 21st Conference of the Parties to the
UNFCCC in December 2015 included the aim of strengthening the global response
to the threat of climate change by "holding the increase in the global
average temperature to well below 2°C above pre-industrial levels and pursuing
efforts to limit the temperature increase to 1.5°C above pre-industrial
levels."
As part of the
decision to adopt the Paris Agreement, the IPCC was invited to produce, in
2018, a Special Report on global warming of 1.5°C above pre-industrial levels
and related global greenhouse gas emission pathways.
The IPCC accepted the invitation, adding that the Special Report would look at these issues in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.
The IPCC accepted the invitation, adding that the Special Report would look at these issues in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.
Global Warming
of 1.5°C is the first in a series of Special Reports to be produced in the
IPCC's Sixth Assessment Cycle. Next year the IPCC will release the Special
Report on the Ocean and Cryosphere in a Changing Climate, and Climate Change
and Land, which looks at how climate change affects land use.
The Summary for
Policymakers (SPM) presents the key findings of the Special Report, based on
the assessment of the available scientific, technical and socio-economic
literature relevant to global warming of 1.5°C.
The Summary for
Policymakers of the Special Report on Global Warming of 1.5°C (SR15) is
available at https://www.ipcc.ch/report/sr15 or www.ipcc.ch.