The Special Report on Global Warming of 1.5 °C (SR15)[a] was published by the Intergovernmental Panel on Climate Change (IPCC) on 8 October 2018. The report, approved in Incheon, South Korea, includes over 6,000 scientific references, and was prepared by 91 authors from 40 countries. In December 2015, the 2015 United Nations Climate Change Conference called for the report. The report was delivered at the United Nations' 48th session of the Intergovernmental Panel on Climate Change (IPCC) to "deliver the authoritative, scientific guide for governments" to deal with climate change. Its key finding is that meeting a 1.5 °C (2.7 °F) target is possible but would require "deep emissions reductions" and "rapid, far-reaching and unprecedented changes in all aspects of society." Furthermore, the report finds that that "limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being" and that a 2 °C temperature increase would exasperate extreme weather, rising sea levels and diminishing Arctic sea ice, coral bleaching, and loss of ecosystems, among other impacts. SR15 also has modelling that shows that "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." The reduction of emissions by 2030 and its associated changes and challenges, including rapid decarbonisation, was a key focus on much of the reporting which was repeated through the world.
The long title of the report 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". According to an article by Phil McKenna at InsideClimate News, SR15 provides a summary of existing research on the impact that a warming of 1.5 °C (equivalent to 2.7 °F) would have on the planet and the necessary steps to limit global warming.
There are three IPCC working groups: Working Group I (WG I), co-chaired by Valerie Masson-Delmotte and Panmao Zhai, covers the physical science of climate change. Working Group II (WG II), co-chaired by Hans-Otto Pörtner and Debra Roberts, examines "impacts, adaptation and vulnerability". The "mitigation of climate change" is dealt with by Working Group III (WG III), co-chaired by Priyardarshi Shukla and Jim Skea. The "Task Force on National Greenhouse Gas Inventories" "develops methodologies for measuring emissions and removals". There are also Technical Support Units that guide "the production of IPCC assessment reports and other products".
Global warming will likely rise to 1.5 °C above pre-industrial levels between 2030 and 2052 if warming continues to increase at the current rate. Anthropogenic greenhouse gas emissions have so far contributed 0.8–1.2 °C (1.4–2.2 °F) of warming. The gases which have already been emitted are unlikely to cause global temperature to rise to 1.5 °C alone, and a global temperature rise to 1.5 °C above pre-industrial levels is avoidable depending on the rate of further emissions. Climate-related risks associated with increasing global warming depend on geographic location, "levels of development and vulnerability", and the speed and reach of climate mitigation and climate adaptation practices.
According to the report, with global warming of 1.5 °C there would be increased risks to "health, livelihoods, food security, water supply, human security, and economic growth."
The report indicates that "rapid and far-reaching transitions in energy, land, urban and infrastructure..., and industrial systems", "unprecedented in terms of scale, but not necessarily in terms of speed" would require "deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options.":2 Examples of actions consistent with the 1.5°C pathway include “shifting to low- or zero-emission power generation, such as renewables; changing food systems, such as diet changes away from land-intensive animal products; electrifying transport and developing ‘green infrastructure’, such as building green roofs, or improving energy efficiency by smart urban planning, which will change the layout of many cities.”
The report says that for limiting warming to below 1.5 degree "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." and even for limiting global warming to below 2°C, CO2 emissions should decline by 20% by 2030 and by 100% to 2075. Non-CO2 emissions should decline in less or more similar ways for limiting warming to 1.5°C or 2°C
The report also states that, in order to avoid reliance on the use of large scale carbon dioxide removal (CDR) in the decades to come, globally, we need a decline in CO2 emissions "well before 2030."
The emission pathways that reach 1.5 °C contained in the report are based on the use of negative emission technology where emissions post 2050 would have to be removed from the air. There are two main groups of geoengineering types in the report, carbon dioxide removal (CDR) and solar radiation management (SRM). The report has special attention for stratospheric aerosol injection because it has the most available literature; however it is still an experimental technology. There are other issues relating to SRM outlined in SR15 outlined in the report, “The impacts of SRM (both biophysical and societal), costs, technical feasibility, governance and ethical issues associated need to be carefully considered.” For CDR the report highlights bioenergy with carbon capture and storage (BECCS). The report notes that apart from afforestation/reforestation and ecosystem restoration “the feasibility of massive-scale deployment of many CDR technologies remains an open question” with areas of uncertainty regarding technology upscaling, governance, ethical issues, policy and carbon cycle. The report notes that CDR technology is in its "infancy" and the "feasibility" is an open question. An analysis of the geoengineering proposals published in Nature Communication confirmed the SR15 stating that "all are in early stages of development, involve substantial uncertainties and risks, and raise ethical and governance dilemmas. Based on present knowledge, climate geoengineering techniques cannot be relied on to significantly contribute to meeting the Paris Agreement temperature goals"
In his 1 October 2018 opening statement at the 48th Session held in Incheon, Korea, Hoesung Lee, who has been Chair of the IPCC since 6 October 2015, described this IPCC meeting as "one of the most important" in its history. Debra Roberts, IPCC contributor called it the "largest clarion bell from the science community". Roberts hopes "it mobilises people and dents the mood of complacency."
In a CBC interview, Paul Romer was asked if the Nobel Prize in economic sciences that he and William Nordhaus received shortly before the SR15 was released, was timed as a message. Romer said that he was optimistic that measures will be taken in time to avert climate catastrophe. Romer compared the angst and lack of political will in imposing a carbon tax to the initial angst surrounding the chlorofluorocarbon (CFC) ban and the positive impact it had on restoring the depleted ozone layer. In giving the Nobel to Nordhaus and Romer, the Royal Swedish Academy of Sciences cited Nordhaus as saying "the most efficient remedy for problems caused by greenhouse gases is a global scheme of universally imposed carbon taxes".
Howard J. Herzog, a senior research engineer at the Massachusetts Institute of Technology, said that carbon capture and storage technologies, except reforestation, are problematic because of their impact on the environment, health and high cost. In the article there is a link to another article that refers to a study published in the scientific journal "Nature Energy". The study says that we can limit warming to 1.5 degrees without carbon capture and storage, by technological innovation and changing lifestyle.
Prime Minister Scott Morrison emphasised that the report was not specifically for Australia but for the whole world. Energy Minister Angus Taylor said the Government would "not be distracted” by the IPCC report saying "A debate about climate change and generation technologies in 2050 won't bring down current power prices for Australian households and small businesses.” Environment Minister Melissa Price said that scientists are “drawing a very long bow” to say coal should be phased out by 2050 and supported new coal-fired power stations pledging not to legislate the Paris targets. Australia is not on track to meet the commitments under Paris agreement according to modelling conducted by ClimateWorks Australia.
Canadian Environment Minister Catherine McKenna acknowledged that the SR15 report would say Canada is not "on track" for 1.5 °C. Canada will not be implementing new plans but it will continue to move forward on a "national price on carbon, eliminating coal-fired power plants, making homes and businesses more energy-efficient, and investing in clean technologies and renewable energy". In response to a question on the sense of urgency of the SR15 report during a 9 October interview on CBC News's Power and Politics Andrew Scheer, the Leader of the Opposition, promised that they are putting forward a "comprehensive plan to reduce CO2 without imposing a carbon tax" which Scheer said "raised costs without actually reducing emissions."
According to The New York Times, the European Union indicated it might add more ambitious reform goals centered around reducing emissions. On 9 October, the Council of the European Union presented their response to SR15 and their position for the Katowice Climate Change Conference of the Parties (COP 24) to be held in Poland in December 2018. Their environment ministers noted recent progress in legislation to reduce greenhouse gas emissions.[b]
The Centre for Science and Environment said the repercussions for developing countries such as India, would be "catastrophic" at 2 °C warming and that the impact even at 1.5 °C described in SR15 is much greater than anticipated. Crop yields would decline and poverty would increase.
The Minister for Climate Change James Shaw said that the Report "has laid out a strong case for countries to make every effort to limit temperature rise to 1.5° Celsius above pre-industrial levels. ... The good news is that the IPCC's report is broadly in line with this Government's direction on climate change and it's highly relevant to the work we are doing with the Zero Carbon Bill."
President Donald Trump said that he had received the report, but wanted to learn more about those who "drew it" before offering conclusions. In an interview with ABC's "This Week" the director of the National Economic Council, Larry Kudlow, stated, "personally, I think the UN study is way too difficult," and that the authors "overestimate" the likelihood for environmental disasters. Since the publication Trump stated in an interview on 60 Minutes that he didn't know that climate change is manmade and that "it'll change back again", the scientists who say it's worse than ever have "a very big political agenda" and that “we have scientists that disagree with [manmade climate change].”
A landmark report from the UN's Intergovernmental Panel on Climate Change warns policymakers of the risks ahead and the changes needed to stop global warming.