Expected climate change by 2100

Overview

The anthropogenic ⁠greenhouse effect⁠ is causing changes to the ⁠climate system⁠. The extent of these changes and their future implications can only be simulated using model calculation, as a wide range of complex interactions must be taken into account. Possible climate changes for the 21st century can be deduced from such model or scenario simulations.

According to the Intergovernmental Panel on Climate Change’s Sixth Assessment Report (IPCC AR6/Synthesis Report 2023), the global surface temperature in the period from 2081–2100 is projected to be approximately 1.4 to 4.4 °C higher, on average, than in the reference period 1850–1900 (depending on the emissions scenario). However, within the statistical uncertainty range of the scenarios, global warming is projected to be between 1.0 and 5.7 °C (IPCC, 2023). If current policy measures and instruments are implemented, global temperatures are expected to rise by around 2.6–2.8 °C by the end of the century, unless greenhouse gas emissions are reduced much more significantly (UNEP, 2025 ). Such a change in temperature would be greater than any natural climate fluctuations observed over the last few centuries, caused, for example, by changes in solar radiation or isolated explosive volcanic eruptions. Moreover, it is occurring at a rate unprecedented in the last 10,000 years.

If greenhouse gas emissions are not reduced, a rise in temperature of 0.25 °C per decade is highly likely over the next 30 years. Even if greenhouse gas concentrations were to stabilise at current levels until 2100, the ⁠climate⁠ will continue to change beyond the 21st century. This is because the greenhouse gas CO₂ in particular remains in the atmosphere for hundreds to thousands of years, and cumulative emissions drive climate change. Furthermore, the Earth’s climate system is very slow to respond and may react to changes with a delay.

Sea level rise

Since 1970, human-induced climate change has been the main cause of the accelerated global rise in sea level. The fact that sea levels are responding somewhat more slowly to climate change than global average temperatures is due to the oceans’ vast capacity to absorb heat. Initially, this led primarily to the thermal expansion of seawater. Since around the year 2000, the melting of glaciers and the Antarctic and Greenland ice sheets has outweighed the effects of thermal expansion on sea level. Once sea-level changes have occurred, they will persist for many centuries. 

The global average sea-level rise has accelerated in recent decades: an average rate of around 3.3 mm/year is reported for 1993–2018 and around 3.7 mm/year for 2006–2018. Compared with the reference period 1995–2014, the IPCC projects a probable rise in global mean sea level of 28 to 55 centimetres by 2100 under a scenario with very low greenhouse gas emissions (SSP1-1. 9) and of around 63 to 101 centimetres under a scenario with very high emissions (SSP5-8.5) (IPCC, 2021).

According to the IPCC, following initial successes in climate action, the very high emissions scenario (SSP5-8.5) is no longer considered plausible. However, more recent analyses show that scenarios broadly in line with the climate action measures currently being implemented could lead to climate change impacts similar to those of SSP5-8.5. The IPCC is currently working on updating the scenarios, which are expected to be published in the next Assessment Report (AR7) in 2028/29. Consequently, the SSP5-8.5 scenario currently continues to serve as a reference for the high-emissions scenario and thus as an upper limit for possible temperature trends up to 2100.

Recent observational data tend to confirm the acceleration in global mean sea-level rise rather than putting it into perspective. The WMO  reported the highest global mean sea level for 2024 since satellite measurements began in 1993. The rate of rise for 2015–2024 was 4.7 mm/year, compared with 2.1 mm/year for 1993–2002. Copernicus  reports an average rate of 3.64 ± 0.25 mm/year for 1999–2025 and an increase in the trend from 2.92 mm/year in 1999–2009 to 3.82 mm/year in 2015–2025. Recent observations show accelerated ice dynamics in polar regions, which are often not yet taken into account in climate models.

Specific changes in the climate system

Entire continents and ocean basins are experiencing considerable climate changes. Models indicate that the following trends will continue into the 21st century (IPCC, 2023).

• The Arctic: The Arctic is warming significantly faster than the global average; this phenomenon is known as ‘Arctic amplification’. According to the IPCC AR6, over the past 50 years, the Arctic has, very likely, warmed more than twice as fast as the global average. More recent observational studies even suggest that, over the last few decades, depending on the time period and the definition of the Arctic, warming has been approximately three to four times faster (AMAP, 2024 )
• Sea ice: Satellite data show that, since 1979, the average annual extent of sea ice in the Arctic has declined significantly over the last four decades; this decline is evident in all months, but is most pronounced in September. Between 1979 and 2023, sea ice extent in March decreased by an average of around 2.8 per cent per decade, and in September by 13.5 per cent per decade. In the 1980s, the average ice extent in September was almost 50 per cent of the March average; in the last 10 years (2014 to 2023), this ratio had fallen to just 35 per cent (Copernicus, 2024).
• Precipitation: On average, global land-based precipitation levels have increased since the mid-20th century. A more rapid increase has been observed, particularly since the 1980s. However, trends vary significantly over the course of the year and from region to region. Predicting future global precipitation patterns is a highly complex and difficult task.
• Extreme weather events: The frequency of heavy rainfall has increased. Cold days and nights, as well as frost, have become less common, whilst hot days and nights, as well as heatwaves, have become more frequent.
• Regional ⁠climate change⁠: Without effective climate action and far-reaching emissions reductions, spatially uneven warming will continue to intensify: land areas, and in particular high northern latitudes, are warming at a faster rate than the global average. This also increases the risk of long-term, and in some cases irreversible, ice loss from the Greenland ice sheet. According to the IPCC’s 2023 Assessment Report, if global warming continues at a rate of around 2–3 °C, the Greenland and West Antarctic ice sheets would be almost completely lost over several millennia, contributing several metres to sea-level rise. A complete melting of the Greenland ice sheet would correspond, in the long term, to a global sea-level rise of around 7 m. Palaeoclimatic evidence from the last interglacial period, around 125,000 years ago, shows that the Greenland ice sheet was significantly smaller under warmer conditions, but probably did not melt away completely. By contrast, today’s warming is predominantly anthropogenic in origin and is occurring at an exceptionally rapid rate in the context of the last few millennia.

Possible events of abrupt climate change

In addition to these gradual climatic changes, rapid changes in the ⁠climate system⁠ could also occur, which are referred to as abrupt climate changes. These are accompanied by serious consequences and feedback processes within the Earth’s climate system that are difficult to predict. Based on current scientific understanding, the likelihood of such an event occurring over the coming decades is considered to be low. However, the actual risk of an abrupt climate change occurring is difficult to assess, as these are non-linear processes and the critical thresholds (Tipping points ) cannot be determined with precision. Nevertheless, the risk increases significantly with every further rise in temperature (see e.g.: Kornhuber et al., 2024). 

Examples are:

• Collapse of thermohaline circulation in the North Atlantic (AMOC) as a result of the warming and/or dilution of the saline water in the North Atlantic,
• Collapse of the West Antarctic Ice Sheet and the associated rise in sea level of several metres,
• Accelerated melting of the Greenland Ice Sheet, thereby triggering an irreversible melting process,
• An increasing risk of permafrost thawing and the consequent release of large quantities of carbon (in the form of methane and carbon dioxide) due to rising temperatures,
• Further release of carbon dioxide and the consequent intensification of climate change due to the widespread die-off of the rainforest, for example in the Amazon region.

Scenario projections show that Europe is warming faster than the global average:

• Over the past decade, the average annual temperature over European land areas was between 2.19 and 2.26 °C higher than in the pre-industrial era. According to all available data sets, 2024 was the warmest year in Europe since instrumental records began around 1850. Temperature anomalies ranged from 2.85 °C to 3.01 °C above pre-industrial levels. Particularly strong warming was recorded in Eastern Europe, Scandinavia and the eastern part of the Iberian Peninsula (EEA, 2025 ).
• Projections from the CMIP6 initiative suggest that temperatures over European land areas will continue to rise more sharply than the global average over the course of this century. Land temperatures in Europe are projected to rise by a further 1.2 to 3.4 °C under the low-emissions scenario (SSP1-2.6) and by 4.1 to 8.5 °C under the very high-emissions scenario (SSP5-8.5) (by 2071–2100, compared with 1981–2010). The greatest warming is expected in north-eastern Europe, northern Scandinavia and the inland regions of the Mediterranean countries. The least warming is expected in western Europe, particularly in the United Kingdom, Ireland, western France, the Benelux countries and Denmark (EEA, 2025 ),
• In general, annual precipitation is increasing in Northern Europe and decreasing in Southern Europe. Seasonally, increased precipitation is projected for Central and Northern Europe, particularly in winter, whilst projections show dryer summers for many parts of Europe
• Heatwaves are becoming more frequent, more intense and are lasting longer. In winter, the number of cold and frosty days continues to decline. The Iberian Peninsula, Central Europe (including the Alpine region), the eastern coast of the Adriatic and southern Greece will be most severely affected by extreme temperatures.
• Heavy rainfall events continue to increase across Europe. In southern Europe in particular, periods of drought are increasing in both duration and frequency.
• Overall, it is expected that southern Europe in particular will be affected by the negative effects of climate change. Desertification, water scarcity and forest fires will increase, particularly in Mediterranean regions.

In order to avoid dangerous anthropogenic disruption to the climate system, international climate policy, in accordance with the Paris Agreement, aims to keep the rise in global average temperature well below 2 °C above pre-industrial levels in the long term and to pursue efforts to limit it to 1.5 °] . According to the IPCC’s 2023 Synthesis Report, global emission pathways that limit warming to 1.5 °C, with no or only limited temporary overshoot, require rapid, deep and sustained reductions in greenhouse gas emissions across all sectors. Under such pathways, global greenhouse gas emissions would have had to peak by 2025 at the latest; compared with 2019 levels, they would need to fall by around 43 per cent by 2030 and by around 60 per cent by 2035 (IPCC, 2023).

However, recent assessments show that current policy trajectories and national climate action plans are insufficient to achieve this. A temporary overshoot of 1.5 °C is now considered highly likely, with any additional warming increasing climate risks (UNEP, 2025). In addition to carbon dioxide, emissions of other greenhouse gases (in particular methane and nitrous oxide, as well as fluorinated compounds) and other substances with indirect climate impacts (such as soot) must also be significantly reduced. Any further warming would considerably increase the risks of climate change. These include extreme weather events, amplifying feedback loops in the Earth’s climate system and the growing danger of crossing tipping points.

Information about ongoing global warming can trigger distressing emotions, such as worry, fear, anger, sadness and despair. Although the situation is serious, this should not lead to resignation. There are many committed individuals, courses of action and successes in climate mitigation. The German Environment Agency is committed to tackling the climate crisis at both national and international levels. We conduct research and provide science-based advice on climate change mitigation and adaptation, and offer solutions and courses of action for, amongst others, policymakers, educational institutions, local authorities and members of the public.