A changing climate

Tipping points

Exceeding a tipping point means an abrupt or extensive shift in part of the climate system, known as a tipping element. Examples of tipping elements that may reach tipping points in the near future are the Greenland and West Antarctic ice sheets, tropical forests, large-scale ocean circulation in the North Atlantic, and permafrost. Exceeding such tipping points can lead to dramatic changes in the climate that can pose serious risks to ecosystems and communities at both the global and regional levels, as well as hamper efforts to limit global warming. However, there is still considerable uncertainty about when tipping points will be reached. Therefore, we need to improve our understanding of tipping points through research.

We do this by using advanced climate models to simulate and analyze key processes such as permafrost, inland ice sheets, and vegetation. The goal is to identify potential early warning signals and create safe emission pathways that can prevent tipping points from being exceeded. We are also researching how exceeding a tipping point can lead to a cascade of further tipping events, as well as how extreme weather events can affect these processes. The results can provide policy guidance by describing the consequences of exceeding tipping points and identifying safe emission pathways.

How can it become both wetter and drier?

When the Earth's temperature rises, evaporation intensifies, which means that more water is transported to the atmosphere. The warmer atmosphere can also hold more water vapor, leading to a global increase in precipitation. However, these changes in precipitation and evaporation vary between different regions and at different times. It is therefore important to conduct research to understand how the changes will affect, for example, flooding, drought, fire risk, and water shortages in different regions and seasons.

We have developed the World Wide HYPE hydrological model, which can describe the effects of climate change on hydrology. The information from Word Wide HYPE is used both by us and by international researchers to analyze how different regions are at risk of becoming wetter or drier at different times of the year, so that communities can adapt to a changing climate. The model is also used internationally in collaboration with local experts, including in Africa and Asia, to build capacity and support communities in managing water-related challenges in a changing climate, as well as to warn when extreme weather leads to flooding.

In order to build a sustainable society, we need to understand how different parts of the hydrological cycle are changing in Sweden. Here, we use our own hydrological model, S-HYPE, together with data from climate models to investigate future changes. We also conduct impact studies to investigate how climate change's impact on the hydrological cycle can affect different sectors, such as agriculture, energy production, and the forestry sector, by studying future forest fire risk.

Extreme weather

Research can clearly link changes in many types of extreme weather to climate change. At SMHI, we investigate how the intensity and frequency of extreme weather may change in a warmer climate. We also conduct research on how society can adapt to extreme weather, such as floods, heat waves, and coastal high water events.

On our topic page on extreme weather, we describe our research on different types of extreme weather in more detail.

A warmer sea

The seas are getting warmer as a result of climate change. We mainly research how the sea areas around Sweden, the Baltic Sea, the Skagerrak/North Sea, and the Arctic Ocean, but also the Southern Ocean, are affected by these changes. Our studies show, for example, that climate change is amplifying the effects of eutrophication in the Baltic Sea, and that by the end of this century, climate change could affect marine habitats and ecosystems as much as all other environmental pressures combined. Another area of research is how the reduction of sea ice in the Arctic is in turn affecting the climate.

Global warming is also leading to rising sea levels. We are developing various future scenarios for sea level rise based on different emission trajectories. In particular, we are studying sea level rise in combination with extreme weather events such as heavy rainfall and storm winds.

On our topic page on the state of the ocean, we describe in more detail our research on how the ocean is affected by a changing climate.

Climate services

According to SMHI's instructions, we are to provide climate information to society. We do this by converting raw data from climate models, observations, and results from climate impact studies into clear and accessible messages. The aim is to increase public knowledge about climate change and to support decision-makers and experts in adapting to new climate conditions and limiting climate impact.

Many low- and middle-income countries are particularly vulnerable to climate change. In these countries, access to reliable climate data is often limited, which makes it difficult to adapt to climate change. To strengthen these countries' ability to meet climate challenges, SMHI participates in several international development partnerships. One example of this is the development of the Climate Information Portal, which SMHI created on behalf of the Green Climate Fund and the WMO. The portal gives users free access to climate information that can be used to seek financial support from the Green Climate Fund, implement climate measures, and adapt to climate change.