The following was copied verbatim from the Wikipedia article on the IPCC on 2020-01-31 for the purpose of giving us something up-to-date, brief and reliable to read based almost directly (Wikipedia) from the experts at the IPCC. The most cogent parts have been emphasized. All the links are working for those of you interested in reading further.
Main article: Special Report on Global Warming of 1.5 °C (published 8 October 2018)
When the Paris Agreement was adopted, the UNFCCC invited the Intergovernmental Panel on Climate Change to write a special report on “How can humanity prevent the global temperature rise more than 1.5 degrees above pre-industrial level”.[100] The completed report, Special Report on Global Warming of 1.5 °C (SR15), was released on 8 October 2018. Its full title 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”.[100]
The finished report summarizes the findings of scientists, showing that maintaining a temperature rise to below 1.5 °C remains possible, but only through “rapid and far-reaching transitions in energy, land, urban and infrastructure…, and industrial systems”.[100][101] Meeting the Paris target of 1.5 °C (2.7 °F) is possible but would require “deep emissions reductions”, “rapid”,[101] “far-reaching and unprecedented changes in all aspects of society”.[102] In order to achieve the 1.5 °C target, CO2 emissions must decline by 45% (relative to 2010 levels) by 2030, reaching net zero by around 2050. Deep reductions in non-CO2 emissions (such as nitrous oxide and methane) will also be required to limit warming to 1.5 °C. Under the pledges of the countries entering the Paris Accord, a sharp rise of 3.1 to 3.7 °C is still expected to occur by 2100. Holding this rise to 1.5 °C avoids the worst effects of a rise by even 2 °C. However, a warming of even 1.5 degrees will still result in large-scale drought, famine, heat stress, species die-off, loss of entire ecosystems, and loss of habitable land, throwing more than 100 Million into poverty. Effects will be most drastic in arid regions including the Middle East and the Sahel in Africa, where fresh water will remain in some areas following a 1.5 °C rise in temperatures but are expected to dry up completely if the rise reaches 2 °C.[103][104][105]
Special Report on climate change and land (SRCCL)
Main article: Special Report on Climate Change and Land
The final draft of the “Special Report on climate change and land” (SRCCL)—with the full title, “Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems” was published online on 7 August 2019.[106] The SRCCL consists of seven chapters, Chapter 1: Framing and Context, Chapter 2: Land-Climate Interactions, Chapter 3: Desertification, Chapter 4: Land Degradation, Chapter 5: Food Security, Chapter 5 Supplementary Material, Chapter 6: Interlinkages between desertification, land degradation, food security and GHG fluxes: Synergies, trade-offs and Integrated Response Options, and Chapter 7: Risk management and decision making in relation to sustainable development.[107][108]
Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC)
Main article: Special Report on the Ocean and Cryosphere in a Changing Climate
The “Special Report on the Ocean and Cryosphere in a Changing Climate” (SROCC) was approved on 25 September 2019 in Monaco.[109] Among other findings, the report concluded that sea level rises could be up to two feet higher by the year 2100, even if efforts to reduce greenhouse gas emissions and to limit global warming are successful; coastal cities across the world could see so-called “storm[s] of the century” at least once a year.[110]