Global warming potential (GWP) is a measure of how much infrared thermal radiation a greenhouse gas added to the atmosphere would absorb over a given time frame, as a multiple of the radiation that would be absorbed by the same mass of added carbon dioxide. GWP is 1 for CO2. For other gases it depends on how strongly the gas absorbs infrared thermal radiation, how quickly the gas leaves the atmosphere, and the time frame being considered. The carbon dioxide equivalent is calculated from GWP. For any gas, it is the mass of CO2 that would warm the earth as much as the mass of that gas. Thus it provides a common scale for measuring the climate effects of different gases. It is calculated as GWP times mass of the other gas.
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the IPCC in 1988. The United Nations endorsed the creation of the IPCC later that year. It has a secretariat in Geneva, Switzerland, hosted by the WMO. It has 195 member states who govern the IPCC. The member states elect a bureau of scientists to serve through an assessment cycle. A cycle is usually six to seven years. The bureau selects experts to prepare IPCC reports. It draws the experts from nominations by governments and observer organizations. The IPCC has three working groups and a task force, which carry out its scientific work.
The United Nations Framework Convention on Climate Change (UNFCCC) established an international environmental treaty to combat "dangerous human interference with the climate system", in part by stabilizing greenhouse gas concentrations in the atmosphere. It was signed by 154 states at the United Nations Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro from 3 to 14 June 1992. Its original secretariat was in Geneva but relocated to Bonn in 1996. It entered into force on 21 March 1994.
There is a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports.
Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly due to emissions from burning fossil fuels such as coal, oil, and natural gas. Mitigation can reduce emissions by transitioning to sustainable energy sources, conserving energy, and increasing efficiency. It is possible to remove carbon dioxide from the atmosphere by enlarging forests, restoring wetlands and using other natural and technical processes. Experts call these processes carbon sequestration. Governments and companies have pledged to reduce emissions to prevent dangerous climate change in line with international negotiations to limit warming by reducing emissions.
The politics of climate change results from different perspectives on how to respond to climate change. Global warming is driven largely by the emissions of greenhouse gases due to human economic activity, especially the burning of fossil fuels, certain industries like cement and steel production, and land use for agriculture and forestry. Since the Industrial Revolution, fossil fuels have provided the main source of energy for economic and technological development. The centrality of fossil fuels and other carbon-intensive industries has resulted in much resistance to climate friendly policy, despite widespread scientific consensus that such policy is necessary.
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming.
The First Assessment Report (FAR) of the Intergovernmental Panel on Climate Change (IPCC) was completed in 1990. It served as the basis of the United Nations Framework Convention on Climate Change (UNFCCC). This report had effects not only on the establishment of the UNFCCC, but also on the first conference of the parties (COP), held in Berlin in 1995. The executive summary of the WG I Summary for Policymakers report that said they were certain that emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases, resulting on average in an additional warming of the Earth's surface. They calculated with confidence that CO2 had been responsible for over half the enhanced greenhouse effect.
In 2005, an international conference titled Avoiding Dangerous Climate Change: A Scientific Symposium on Stabilisation of Greenhouse Gases examined the link between atmospheric greenhouse gas concentration and global warming and its effects. The conference name was derived from Article 2 of the charter for the United Nations Framework Convention on Climate Change The conference explored the possible impacts at different levels of greenhouse gas emissions and how the climate might be stabilized at a desired level. The conference took place under the United Kingdom's presidency of the G8, with the participation of around 200 "internationally renowned" scientists from 30 countries. It was chaired by Dennis Tirpak and hosted by the Hadley Centre for Climate Prediction and Research in Exeter, from 1 February to 3 February. The conference was one of many meetings leading up to the 2015 Paris Agreement, at which the international community agreed to limit global warming to no more than 2 °C in order to have a 50-50 chance of avoiding dangerous climate change. However, a 2018 published study points at a threshold at which temperatures could rise to 4 or 5 degrees through self-reinforcing feedbacks in the climate system, suggesting the threshold is below the 2 degree temperature target.
This is a list of climate change topics.
Climate change in New Zealand involves historical, current and future changes in the climate of New Zealand; and New Zealand's contribution and response to global climate change. Summers are becoming longer and hotter, and some glaciers have melted completely and others have shrunk. In 2021, the Ministry for the Environment estimated that New Zealand's gross emissions were 0.17% of the world's total gross greenhouse gas emissions. However, on a per capita basis, New Zealand is a significant emitter, the sixth highest within the Annex I countries, whereas on absolute gross emissions New Zealand is ranked as the 24th highest emitter.
The climate change policy of the United States has major impacts on global climate change and global climate change mitigation. This is because the United States is the second largest emitter of greenhouse gasses in the world after China, and is among the countries with the highest greenhouse gas emissions per person in the world. In total, the United States has emitted over 400 billion metric tons of greenhouse gasses, more than any country in the world.
Climate change scenarios or socioeconomic scenarios are projections of future greenhouse gas (GHG) emissions used by analysts to assess future vulnerability to climate change. Scenarios and pathways are created by scientists to survey any long term routes and explore the effectiveness of mitigation and helps us understand what the future may hold this will allow us to envision the future of human environment system. Producing scenarios requires estimates of future population levels, economic activity, the structure of governance, social values, and patterns of technological change. Economic and energy modelling can be used to analyze and quantify the effects of such drivers.
Climate change in Europe has resulted in an increase in temperature of 2.3 °C (2022) in Europe compared to pre-industrial levels. Europe is the fastest warming continent in the world. Europe's climate is getting warmer due to anthropogenic activity. According to international climate experts, global temperature rise should not exceed 2 °C to prevent the most dangerous consequences of climate change; without reduction in greenhouse gas emissions, this could happen before 2050. Climate change has implications for all regions of Europe, with the extent and nature of impacts varying across the continent.
A carbon budget is a concept used in climate policy to help set emissions reduction targets in a fair and effective way. It looks at "the maximum amount of cumulative net global anthropogenic carbon dioxide emissions that would result in limiting global warming to a given level". When expressed relative to the pre-industrial period it is referred to as the total carbon budget, and when expressed from a recent specified date it is referred to as the remaining carbon budget.
The history of climate change policy and politics refers to the continuing history of political actions, policies, trends, controversies and activist efforts as they pertain to the issue of global warming and other environmental anomalies. Dryzek, Norgaard, and Schlosberg suggest that critical reflection on the history of climate policy is necessary because it provides 'ways to think about one of the most difficult issues we human beings have brought upon ourselves in our short life on the planet’.
Sustainable Development Goal 13 is to limit and adapt to climate change. It is one of 17 Sustainable Development Goals established by the United Nations General Assembly in 2015. The official mission statement of this goal is to "Take urgent action to combat climate change and its impacts". SDG 13 and SDG 7 on clean energy are closely related and complementary.
Green recovery packages are proposed environmental, regulatory, and fiscal reforms to rebuild prosperity in the wake of an economic crisis, such as the COVID-19 pandemic or the Global Financial Crisis (GFC). They pertain to fiscal measures that intend to recover economic growth while also positively benefitting the environment, including measures for renewable energy, efficient energy use, nature-based solutions, sustainable transport, green innovation and green jobs, amongst others.
The Sixth Assessment Report (AR6) of the United Nations (UN) Intergovernmental Panel on Climate Change (IPCC) is the sixth in a series of reports which assess scientific, technical, and socio-economic information concerning climate change. Three Working Groups covered the following topics: The Physical Science Basis (WGI); Impacts, Adaptation and Vulnerability (WGII); Mitigation of Climate Change (WGIII). Of these, the first study was published in 2021, the second report February 2022, and the third in April 2022. The final synthesis report was finished in March 2023.
Joeri Rogelj is a Belgian climate scientist working on solutions to climate change. He explores how societies can transform towards sustainable futures. He is a Reader in Climate Science and Policy at the Centre for Environmental Policy (CEP) and Director of Research at the Grantham Institute – Climate Change and Environment, both at Imperial College London. He is also affiliated with the International Institute for Applied Systems Analysis. He is an author of several climate reports by the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Environment Programme (UNEP), and a member of the European Scientific Advisory Board for Climate Change.
