We have 12 years to limit climate change catastrophe: this the message that IPCC report has globally launched to governments and policymakers.
The Special Report on Global Warming of 1.5º 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. 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.
1.5 degrees Celsius of warming will be much worse than the 1 degree Celsius we’re experiencing now: “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.
Understanding Global Warming of 1.5°C
Human activities are estimated to have caused approximately 1.0°C of global warming above pre-industrial levels, with a likely range of 0.8°C to 1.2°C: global warming is likely to reach 1.5°C between 2030 and 2052 if it continues to increase at the current rate.
Warming greater than the global annual average is being experienced in many land regions and seasons, including two to three times higher in the Arctic. Trends in intensity and frequency of some climate and weather extremes have been detected over time spans during which about 0.5°C of global warming occurred: this assessment is based on several lines of evidence, including attribution studies for changes in extremes since 1950. Climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5°C and increase further with 2°C. Exposure to multiple and compound climate-related risks increases between 1.5°C and 2°C of global warming, with greater proportions of people both so exposed and susceptible to poverty in Africa and Asia; for global warming from 1.5°C to 2°C, risks across energy, food, and water sectors could overlap spatially and temporally, creating new and exacerbating current hazards, exposures, and vulnerabilities that could affect increasing numbers of people and regions.
Transition pathways and the global call to action
A 1.5˚C limit to warming is not safe for all, but risks associated with warming are substantially lower at 1.5˚C than 2˚C.
Pathways limiting global warming to 1.5°C would require rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems: these systems transitions imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options.
In energy systems, modelled global pathways limiting global warming to 1.5°C require unprecedented efforts to cut fossil-fuel use in half in less than 15 years and eliminate their use almost entirely in 30 years: it means “no home, business, or industry heated by gas or oil; no vehicles powered by diesel or gasoline; all coal and gas power plants shuttered; the petrochemical industry converted wholesale to green chemistry; and heavy industry like steel and aluminum production either using carbon-free energy sources or employing technology to capture CO2 emissions and permanently store it”.
Everyone – countries, cities, the private sector, individuals — will need to strengthen their action, without delay.
Without transformation in society and rapid implementation of ambitious emissions cuts, limiting warming to 1.5˚C while achieving sustainable development will be exceedingly difficult, but not impossible: Dr. Gavin A. Schmidt, Director of GISS and Principal Investigator for the GISS Model Earth System Model, remembered to everyone: “The key thing from this report is that the best time to have reduced emissions was 25 years ago, but the second best to reduce emissions is right now."