Mise à jour: 31 Oct 2021

Climate change is one of the most pervasive and threatening issues of our time, with far-reaching impacts in the 21st century. Climate change is expected to have unprecedented implications on where people can settle, grow food, build cities, and rely on functioning ecosystems for the services they provide. In many places, temperature changes and sea-level rise are already putting ecosystems under stress and affecting human well-being.

Global Warming of 1.5°C

In October 2018, the Intergovernmental Panel on Climate Change (IPCC) issued a special report on the impacts of global warming of 1.5°C, finding that limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society. With clear benefits to people and natural ecosystems, the report found that limiting global warming to 1.5°C compared to 2°C could go hand in hand with ensuring a more sustainable and equitable society. While previous estimates focused on estimating the damage if average temperatures were to rise by 2°C, this report shows that many of the adverse impacts of climate change will come at the 1.5°C mark.

The report also highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5ºC compared to 2ºC, or more. For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2ºC.

The Human Fingerprint on Greenhouse Gases

Greenhouse gases occur naturally and are essential to the survival of humans and millions of other living things, by keeping some of the sun’s warmth from reflecting back into space and making Earth livable. But after more than a century and a half of industrialization, deforestation, and large scale agriculture, quantities of greenhouse gases in the atmosphere have risen to record levels not seen in three million years. As populations, economies and standards of living grow, so does the cumulative level of greenhouse gas (GHGs) emissions.

There are some basic well-established scientific links:

  • The concentration of GHGs in the earth’s atmosphere is directly linked to the average global temperature on Earth;
  • The concentration has been rising steadily, and mean global temperatures along with it, since the time of the Industrial Revolution;
  • The most abundant GHG, accounting for about two-thirds of GHGs, carbon dioxide (CO2), is largely the product of burning fossil fuels.

Impacts of Climate Change

Human Health

According to IPCC, any increase in global warming is projected to affect human health, with primarily negative consequences. Lower risks are projected at 1.5°C than at 2°C for heat-related morbidity and mortality and for ozone-related mortality if emissions needed for ozone formation remain high. Urban heat islands often amplify the impacts of heatwaves in cities. Risks from some vector-borne diseases, such as malaria and dengue fever, are projected to increase with warming from 1.5°C to 2°C, including potential shifts in their geographic range.

The World Health Organization (WHO) COP26 Special Report on Climate Change and Health spells out the global health community’s prescription for climate action based on a growing body of research that establishes the many and inseparable links between climate and health. The WHO report is launched at the same time as an open letter, signed by over two thirds of the global health workforce – 300 organizations representing at least 45 million doctors and health professionals worldwide, calling for national leaders and COP26 country delegations to step up climate action. The report and open letter come as unprecedented extreme weather events and other climate impacts are taking a rising toll on people’s lives and health. Increasingly frequent extreme weather events, such as heatwaves, storms and floods, kill thousands and disrupt millions of lives, while threatening healthcare systems and facilities when they are needed most. Changes in weather and climate are threatening food security and driving up food-, water- and vector-borne diseases, such as malaria, while climate impacts are also negatively affecting mental health.

Land and Water

On land, impacts on biodiversity and ecosystems, including species loss and extinction, have already been observed with rising temperatures, increased ocean acidity and decreased ocean oxygen levels. These terrestrial, freshwater and coastal ecosystems provide value and services to humans.

Global warming of 1.5°C is projected to shift the ranges of many marine species to higher latitudes as well as increase the amount of damage to many ecosystems. It is also expected to drive the loss of coastal resources and reduce the productivity of fisheries and aquaculture (especially at low latitudes).

The Fifth Assessment Report provides a comprehensive assessment of sea level rise, and its causes, over the past few decades. It also estimates cumulative CO2 emissions since pre-industrial times and provides a CO2 budget for future emissions to limit warming to less than 2°C. About half of this maximum amount was already emitted by 2011. The report found that:

  • From 1880 to 2012, the average global temperature increased by 0.85°C.
  • Oceans have warmed, the amounts of snow and ice have diminished and the sea level has risen. From 1901 to 2010, the global average sea level rose by 19 cm as oceans expanded due to warming and ice melted. The sea ice extent in the Arctic has shrunk in every successive decade since 1979, with 1.07 × 106 km² of ice loss per decade.
  • Given current concentrations and ongoing emissions of greenhouse gases, it is likely that by the end of this century global mean temperature will continue to rise above the pre-industrial level. The world’s oceans will warm and ice melt will continue. Average sea level rise is predicted to be 24–30 cm by 2065 and 40–63 cm by 2100 relative to the reference period of 1986–2005. Most aspects of climate change will persist for many centuries, even if emissions are stopped.

There is alarming evidence that important tipping points, leading to irreversible changes in major ecosystems and the planetary climate system, may already have been reached or passed. Ecosystems as diverse as the Amazon rainforest and the Arctic tundra, may be approaching thresholds of dramatic change through warming and drying. Mountain glaciers are in alarming retreat and the downstream effects of reduced water supply in the driest months will have repercussions that transcend generations.

Land Temperature

Rising land temperatures reinforce need for urgent action. The earth’s mean near-surface temperature has risen by more than 1°C compared to the pre-industrial era and, at current rates, this will reach 1.5°C by around 2040 and possibly earlier. To turn this around, we all need to implement lifestyle changes, provide financial and technical assistance for developing nations, and support for nature-based solutions, like reforestation.

Source: UNEP Climate Action Note (October 2021)

Ocean Temperature

Our oceans are getting warmer and sea levels are rising. Ice sheets and glaciers are melting, pushing sea levels higher and threatening coastal cities and settlements. Rising sea levels mean storm surges will be deadlier. Carbon dioxide emissions also lead to ocean acidification, which harms marine species, including corals. And things could get worse: as the world gets hotter, it is more likely the Arctic will be ice-free in summer, further disrupting ocean circulation and ecosystems.

Source: UNEP Climate Action Note (October 2021)


Wildfires raise spectre of terrifying new normal in hotter world. Huge wildfires in Australia, the Amazon, California, the Congo basin and even in the Arctic are sobering reminders of the human, economic and environmental costs of climate change. Record temperatures, heatwaves and droughts help spark wildfires. The global average temperature is now around 1.1°C higher than at the beginning of last century, meaning wildfires and megafires could become a new normal in some countries.

Source: UNEP Climate Action Note (October 2021)

Climate Action

According to the United Nations Environment Programme (UNEP), the climate emergency we currently face requires adequate and immediate action. It is one of the most pervasive and threatening crises of our time.

As the climate emergency intensifies, the transition towards climate stability becomes increasingly critical. Progress will depend on countries and their ability to cover ground on their commitments under the Paris Agreement and eventually, their collective contributions to keep the global average temperature well below 2°C.

If we continue along our current path, scientists say that the consequences will be devastating, having implications on where we live, how we grow food and other services vital to our well-being. A 2°C increase could mean more heat waves, a ten-fold increase in Arctic ice-free summers and a complete wipe-out of the world’s coral reefs, home to millions of species.

Mitigation and Instruments

Rapid, far-reaching and long-term transitions in energy, land use, infrastructure (including in transportation and buildings), and industrial systems are needed to limit climate change. According to the IPCC, such transitions are unprecedented in terms of scale, but not necessarily in terms of speed, and imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options.

In addition, 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. This means that any remaining emissions would need to be balanced by removing CO2 from the air.

Green Economy

According to the ILO, if properly managed, climate change action can lead to more and better jobs. Both adaptation to climate change and measures to mitigate greenhouse gas (GHG) emissions offer opportunities to create new jobs, while securing existing ones. A transition to a low-carbon, greener economy will imply the creation of new jobs in environmentally friendly production processes and outputs, whereas other jobs will be at risk, in particular in those sectors with fewer options for a transition towards a more sustainable ways of production.

United Nations Framework Convention on Climate Change

The UN family is at the forefront of the effort to save our planet. In 1992, its “Earth Summit” produced the United Nations Framework Convention on Climate Change (UNFCCC) as a first step in addressing the climate change problem. Today, it has near-universal membership. The 197 countries that have ratified the Convention are Parties to the Convention. The ultimate aim of the Convention is to prevent “dangerous” human interference with the climate system.

Kyoto Protocol

By 1995, countries launched negotiations to strengthen the global response to climate change, and, two years later, adopted the Kyoto Protocol. The Kyoto Protocol legally binds developed country Parties to emission reduction targets. The Protocol’s first commitment period started in 2008 and ended in 2012. The second commitment period began on 1 January 2013 and will end in 2020. There are now 197 Parties to the Convention and 192 Parties to the Kyoto Protocol.

Paris Agreement

At the 21st Conference of the Parties in Paris in 2015, Parties to the UNFCCC reached a landmark agreement to combat climate change and to accelerate and intensify the actions and investments needed for a sustainable low carbon future. The Paris Agreement builds upon the Convention and – for the first time – brings all nations into a common cause to undertake ambitious efforts to combat climate change and adapt to its effects, with enhanced support to assist developing countries to do so. As such, it charts a new course in the global climate effort.

2019 Climate Action Summit

On 23 September 2019, Secretary-General António Guterres convened a Climate Summit to bring world leaders of governments, the private sector and civil society together to support the multilateral process and to increase and accelerate climate action and ambition.


The UK is hosting the 26th UN Climate Change Conference of the Parties (COP26) in Glasgow on 31 October – 12 November 2021. The COP26 summit brings parties together to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change.


1. Secure global net zero by mid-century and keep 1.5 degrees within reach

Countries are being asked to come forward with ambitious 2030 emissions reductions targets that align with reaching net zero by the middle of the century.

To deliver on these stretching targets, countries will need to:

  • Accelerate the phase-out of coal
  • Curtail deforestation
  • Speed up the switch to electric vehicles
  • Encourage investment in renewables.

2. Adapt to protect communities and natural habitats

The climate is already changing and it will continue to change even as we reduce emissions, with devastating effects.

At COP26 we need to work together to enable and encourage countries affected by climate change to:

  • Protect and restore ecosystems
  • Build defenses, warning systems and resilient infrastructure and agriculture to avoid loss of homes, livelihoods and even lives

3. Mobilize finance

To deliver on the first two goals, developed countries must make good on their promise to mobilize at least USD 100 billion in climate finance per year by 2020.

International financial institutions must play their part and we need work towards unleashing the trillions in private and public sector finance required to secure global net zero.

4. Work together to deliver

We can only rise to the challenges of the climate crisis by working together.

At COP26 we must:

  • Finalize the Paris Rulebook (the detailed rules that make the Paris Agreement operational)
  • Accelerate action to tackle the climate crisis through collaboration between governments, businesses and civil society.

The Role of Geneva

Organizations are listed in alphabetical order

Center for International Environmental Law (CIEL)

CIEL is committed to applying a human rights-based approach as a means to protect the peoples and communities on the frontline of climate change. In doing so, it works to design and integrate policies to safeguard rights and ecosystems and to ensure effective public participation within key climate institutions and mechanisms. CIEL also provide support and build the capacity of peoples and communities adversely affected by climate impacts and climate policies to support their direct participation in those decisions that affect their lives and livelihoods, including working with partners to develop new legal strategies to hold corporations accountable and accelerate the transition away from fossil fuels.


Earthjustice works with partners to end the use of fossil fuels and bring about a swift and just transition to zero carbon emissions and 100% clean energy.

Group on Earth Observations (GEO)

Earth observations relevant to climate action are not limited to weather or climate, but are much broader and include terrestrial and socio-economic variables. GEO makes available Earth observations in support of effective policy responses for climate change adaptation, mitigation and other specific provisions, working with partners to enhance global observation systems for climate action. GEO will be present at COP26 with a series of events to promote the role of Earth observations in providing actionable information for climate adaptation and mitigation.

Intergovernmental Panel on Climate Change (IPCC)

The IPCC was set up to provide an objective source of scientific information. In 2013, the IPCC provided more clarity about the role of human activities in climate change when it released its Fifth Assessment Report. It is categorical in its conclusion: Climate change is real and human activities are the main cause.

International Committee of the Red Cross (ICRC)

The ICRC works to adapt its response to support populations coping with the dual shocks of climate risks and conflicts. In 2020, the ICRC also released the report « When rain turns to dust » illustrating how countries mired in conflict are disproportionately impacted by climate variability and extremes, due to the limited adaptive capacity of people, systems, and institutions already coping with the consequences of conflicts.

International Emissions Trading Association (IETA)

The mission of IETA is to empower business to engage in climate action, advancing the objectives of the United Nations Framework Convention on Climate Change and the Paris Agreement as informed by IPCC science and establish effective market-based trading systems for greenhouse gas (GHG) emissions and removals that are environmentally robust, fair, open, efficient, accountable and consistent across national boundaries.

International Federation of Red Cross and Red Crescent Societies (IFRC)

The IFRC held its first-ever virtual climate summit, Climate: Red, on 9-10 September 2020. It brought together members, staff, youth activists, government officials, experts, and indigenous leaders from around the world to discuss how to tackle the climate emergency. Together with the ICRC, the IFRC has also led the development of a Climate and Environment Charter for Humanitarian Organizations to guide the sector as it responds to these crises and to rally collective action.

International Institute for Sustainable Development (IISD)

IISD is actively involved in the two main responses to climate change: adaptation and mitigation. It partners with countries to help them cope with a changing climate and transition to clean energy as quickly as possible. By backing major initiatives like fossil fuel subsidy reform and climate adaptation planning, IISD uses its expertise to lessen the flow and concentration of heat-trapping greenhouse gases and help people build a more resilient future.

International Labour Organization (ILO)

Spearheaded by the ILO it launched the Climate Action for Jobs Initiative by United Nations Secretary-General António Guterres. The initiative brings together governments, workers’ and employers’ organizations, international institutions, academia and civil society to place jobs at the heart of ambitious climate action and to promote a just transition.

International Telecommunication Union (ITU)

Through its Radiocommunication sector (ITU-R), Standardization sector (ITU-T) and Development sector (ITU-D), ITU covers the role of digital technologies within climate change, to tackle e-waste and facilitate energy efficiency​

International Union for Conservation of Nature (IUCN)

The IUCN assesses the impacts of climate change on species and ecosystems. Through its work on ecosystem-based mitigation, adaptation and disaster risk reduction, it also highlights the important role of nature-based solutions to climate change. It also works to ensure that climate policy and action are gender-responsive, socially inclusive and take into account to the needs of the most vulnerable.

Partnership for Environment and Disaster Risk Reduction (PEDRR)

PEDRR is a global partnership of 24 organizations that promotes ecosystem management as a key strategy to enable vulnerable communities and countries to reduce disaster risk and build resilience to disasters and climate change.

Platform on Disaster Replacement

Climate refugees are on the increase and the Platform on Disaster Displacement is a State-led initiative that aims to follow up on the work started by the Nansen Initiative and to implement the Nansen Initiative – Agenda for the Protection of Cross-Border Displaced Persons in the Context of Disasters and Climate Change, endorsed by more than 100 States in October 2015.

Regions of Climate Action (R20)

R20 works to support sub-national governments around the world to develop and finance low-carbon and climate resilient infrastructure projects in the fields of renewable energy, energy efficient lighting and waste optimization.

United Nations Office for Disaster Risk Reduction (UNDRR)

UNDRR UNDRR oversees the implementation of the Sendai Framework for Disaster Risk Reduction 2015-2030, supporting countries in its implementation, monitoring and sharing what works in reducing existing risk and preventing the creation of new risk. As climate-related risks are increasingly affecting people around the world, UNDRR is also actively promoting climate adaptation to reduce these risks.

United Nations Economic Commission for Europe (UNECE)

The UNECE region is a major source of greenhouse gas emissions, responsible for 34% of the world’s CO2 emissions from fossil fuel combustion. The people of the region are increasingly feeling the impacts of climate change – from wildfires to flooding, heatwaves and drought. Through its norms, standards, conventions and policy assistance, UNECE provides key tools supporting countries in their climate change mitigation and adaptation efforts.

United Nations Environment Programme (UNEP)

The work of UNEP on climate action cuts across the fields of science, policy, technology and finance. It empowers countries to pursue low-emission development and boost their capacity to adapt and be resilient to climate heating. UNEP is also working to implement the Paris Agreement and its contributions include bringing science to policymakers, playing a leading role in transformative global partnerships, and helping dozens of countries develop national plans to cut greenhouse gas emissions. In addition, UNEP equips countries to seize new investment opportunities that reduce greenhouse gas emissions from deforestation and forest degradation and supports the development of new finance models to accelerate the transition to a green economy. Through the Climate Finance Unit, UNEP also focuses on supporting developing countries to access climate finance (directly and through accredited entities) from the Green Climate Fund (GCF), the Global Environment Facility (GEF), and the Adaptation Fund (AF) as well as through other bilateral or multilateral public sources.

United Nations Human Rights Council

In a resolution (A/HRC/44/L.5) on human rights and climate change, the UN Human Rights Council decided to incorporate a panel discussion focusing on the adverse impact of climate change on the full and effective enjoyment of human rights by older persons and best practices and lessons learned in the promotion and protection of the rights of older persons.  The Council also requested a study on the promotion and protection of the rights of older persons in the context of climate change, including their particular vulnerabilities, and to provide all the human and technical assistance necessary for the effective and timely realization of the above-mentioned panel discussion and the summary report thereon.

UN-REDD Programme

Since 2008 the UN-REDD Programme  has been supporting 65 partner countries in their nationally led efforts to become “REDD+ ready” and qualify for results-based payments. Within the UN-REDD Programme, UNEP leads on private sector engagement, safeguards, knowledge management and communications. The Paris Climate Agreement also recognizes REDD+ and the central role of forests in Article 5. To date, 118 countries have included forest and land use in their Nationally Determined Contributions pledges.

World Business Council for Sustainable Development (WBCSD)

The Climate Policy Working Group members of WBCSD meet regularly to shape key messages, share insights and plan for events to bring the voice of business. Topical issues today include Paris Agreement implementation and ambition, carbon pricing and Science-Based Targets (SBTs).

World Economic Forum (WEF)

The WEF Climate Change Intelligence is a visual representation of climate change and provides an overview and the key trends affecting it, along with summaries and links to the latest research and analysis on each of the trends.

World Health Organization (WHO)

The WHO indicates that the world population is encountering unfamiliar human-induced changes in the lower and middle atmospheres and world-wide depletion of various other natural systems. Beyond the early recognition that such changes would affect economic activities, infrastructure and managed ecosystems, there is now recognition that global climate change poses risks to human population health. Climate change is emerging as a major theme in population health research, social policy development, and advocacy. Consideration of global climatic-environmental hazards to human health will become a central role in the sustainability transition debate.

World Meteorological Organization (WMO)

The WMO helps its members to monitor the Earth’s climate on a global scale so that reliable information is available to support evidence-based decision-making on how to best adapt to a changing climate and manage risks associated with climate variability and extremes. Climate information is essential for monitoring the success of efforts to reduce greenhouse gas emissions that contribute to climate change, as well as for promoting efforts to increase energy efficiency and to transition to a carbon-neutral economy.


WWF works to tackle the climate crisis in a variety of ways. From encouraging governments to implement more ambitious climate policies, to supporting the shift to renewable energy, to working with cities, businesses and communities to create a climate-resilient, net-zero future. WWF’s goal is to adaptively halve greenhouse gas emissions through a stark reduction in energy demand, an increase of at least 40% of non-hydro renewable energy in electricity mix and the implementation of nature-based solutions at scale which ensure people and nature resilience to climate change.

Events, Jobs & Learning

International Geneva is buzzing with activities around climate issues. Check out our interactive climate page to find conferences, webinars and events of all sorts, as well as courses, job opportunities, publications, links to organizations and experts, etc.

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