Global Warming of 1.5 °C

Global Warming of 1.5 °C
Intergovernmental Panel on Climate Change · Public domain · source
Name	Global Warming of 1.5 °C
Time frame	21st century
Caused by	Anthropogenic greenhouse gas emissions
Notable reports	Intergovernmental Panel on Climate Change Special Report on Global Warming of 1.5 °C

Contents

Global Warming of 1.5 °C The target of 1.5 °C above pre-industrial levels is a policy and scientific benchmark addressed by actors including the United Nations Framework Convention on Climate Change, the Intergovernmental Panel on Climate Change, and the Paris Agreement. The benchmark informs deliberations by institutions such as the World Bank, the International Energy Agency, and national bodies including the European Commission and the United States Environmental Protection Agency. Scientific assessments draw upon data from observatories like the Mauna Loa Observatory, paleoclimate archives such as the Vostok ice core, and modelling centers including the Met Office Hadley Centre.

Background and scientific basis

The 1.5 °C benchmark emerged from negotiations at the Paris Agreement and was analyzed in depth by the Intergovernmental Panel on Climate Change's Special Report, which synthesized work from research groups at institutions such as NASA, NOAA, CSIRO, ETH Zurich, Potsdam Institute for Climate Impact Research, Lawrence Berkeley National Laboratory, and Tyndall Centre for Climate Change Research. Paleoclimate context is provided by studies of the Last Glacial Maximum, Holocene variability, and instrumental records maintained by the HadCRUT dataset, GISS, and Berkeley Earth. Radiative forcing concepts link to work by Skeie et al., while carbon cycle dynamics invoke research from James Hansen-affiliated groups and modelling frameworks such as CMIP5 and CMIP6. The role of greenhouse gases references emissions inventories from the International Energy Agency, national submissions to the UNFCCC, and sectoral analyses by the Intergovernmental Panel on Climate Change Working Group III. Attribution science cites methods developed at Met Office Hadley Centre and National Center for Atmospheric Research.

Observed changes documented by the IPCC include trends recorded at Mauna Loa Observatory and documented in assessments by NOAA and NASA. Impacts on cryosphere elements reference observations from Greenland ice sheet, Antarctic ice sheet, and mountain glaciers like those in the Himalayas and Alps. Sea level rise projections connect to studies by the U.S. Geological Survey, International Panel on Sea Level Rise researchers, and the Intergovernmental Panel on Climate Change. Ecosystem responses draw on literature involving IPBES, World Wildlife Fund, Ramsar Convention sites, and studies of coral reefs including Great Barrier Reef research. Human health and food security impacts connect to reports by the World Health Organization, Food and Agriculture Organization, and analyses in Lancet commissions. Extreme event attribution uses methods from World Weather Attribution, European Centre for Medium-Range Weather Forecasts, and NOAA National Centers for Environmental Information. Societal vulnerability assessments reference work by United Nations Development Programme, UNEP, and national agencies like Environment Canada.

Remaining carbon budgets are estimated by the Intergovernmental Panel on Climate Change using models from IPSL, NCAR, GFDL, and Hadley Centre. Pathways consistent with 1.5 °C include scenarios developed by the Integrated Assessment Models community, with contributions from teams at IIASA, MIT's Joint Program, Princeton University's REPEAT analyses, and Stanford University's Energy Modeling Forum. Negative emissions options considered by scenario sets involve technologies and strategies investigated by Bioenergy with carbon capture and storage projects, research programs at Drax Group pilot sites, carbon dioxide removal studies funded by the European Union Horizon 2020 program, and direct air capture initiatives by companies like Climeworks assessed in academic work at Caltech. Uncertainty discussions cite the IPCC's treatment of climate sensitivity, aerosol forcing debates involving groups such as Max Planck Institute for Meteorology, and assessments of permafrost carbon feedbacks led by researchers at University of Alaska Fairbanks.

Mitigation strategies aligned with 1.5 °C rely on decarbonization in energy, transport, industry, and land use, building on policy instruments deployed by the European Union Emissions Trading System, national measures in China and India, and subnational initiatives in California and British Columbia. Technological portfolios emphasize renewable deployment tracked by International Renewable Energy Agency, electrification analyses from National Renewable Energy Laboratory, efficiency standards developed by International Energy Agency, and low-carbon hydrogen roadmaps discussed by Hydrogen Council. Land-use strategies draw on conservation frameworks from the Convention on Biological Diversity, afforestation programs in Brazil, and peatland restoration projects supported by Wetlands International. Carbon pricing and fiscal measures are informed by research from the World Bank's carbon pricing reports, carbon capture demonstrations funded by U.S. Department of Energy, and policy design analyses at Columbia University's Center on Global Energy Policy.

Adaptation measures for a 1.5 °C world are cataloged in guidance by the United Nations Framework Convention on Climate Change, national adaptation plans filed by Small Island Developing States and Least Developed Countries, and financing mechanisms such as the Green Climate Fund and Global Environment Facility. Urban resilience initiatives draw on programs by C40 Cities, ICLEI, and metropolitan projects in Tokyo, New York City, and London. Agricultural adaptation connects to innovation supported by CGIAR centers, International Fund for Agricultural Development projects, and extension services in countries like Kenya and Bangladesh. Disaster risk reduction aligns with standards from the Sendai Framework for Disaster Risk Reduction and operational agencies such as the Red Cross and UN Office for the Coordination of Humanitarian Affairs.

Debates over ambition and burden-sharing invoke principles established under the Paris Agreement, analyses by the World Bank, International Monetary Fund, and equity frameworks developed in scholarship at Harvard University, Oxford University's Environmental Change Institute, and Yale University. Ethical arguments reference works by scholars linked to the IPCC and philosophers associated with United Nations climate justice fora, and legal implications are pursued in cases before courts in Netherlands and Philippines. Development pathways for low-income nations consider investment needs assessed by the International Finance Corporation, Asian Development Bank, and African Development Bank, while loss and damage discussions are advanced in UNFCCC negotiations and supported by research institutions like Stockholm Environment Institute.