Adaptation to Climate Change
Climate change is progressing rapidly, and its impacts are already visible in Finland. In general, average temperatures are rising, especially in winter. In addition, annual precipitation is increasing throughout the country. However, annual variability is significant, especially in precipitation.
In Northern Ostrobothnia, the climate statistics show that climate has already warmed: the period 1991–2020 was about 0.6 °C warmer than the period 1981–2010. Depending on the amount of global greenhouse gas emissions in the coming years, the average temperature in our region will be about 1.9–3.0 °C higher by mid-21st century than today.
Precipitation in Northern Ostrobothnia is expected to increase in all seasons, but most significantly in winter. Regional variability, especially in the occurrence of snow and frost, will continue. The amount of snow will decrease particularly in coastal Ostrobothnia, as rising temperatures cause precipitation to fall more often as rain instead of snow. Moving eastward, the amount of snow may first increase, as temperatures there remain below zero more often. For some other weather phenomena the impacts of climate change are more uncertain. For example, the occurrence of severe storms is influenced by many different factors, making changes in their frequency and intensity more difficult to predict.
Since the effects of climate change mitigation measures are seen with a delay, the climatic conditions will inevitably continue to change in the coming decades, also in Oulu. Therefore, adaptation is a key element in city’s climate work. The more successful mitigation, the less adaptation is required, and vice versa.
Climate change adaptation refers to all the actions taken to prepare for and cope with changes in climatic and weather conditions. The goal is to reduce harmful impacts, such as storm damage, and to benefit from positive impacts, such as the increase of the growing season length. However, it is not always clear whether changes in climate will have negative or positive consequenses. Something beneficial in the short term can become harmful over a longer period. A change that harms one sector of society may improve the operational conditions for another sector. Similarly, adaptation measures taken in one location can hinder climate work elsewhere. Cooperation between various parties/stakeholders, such as land use planning, construction, water management, rescue services, research, and healthcare, is thus a requisite for all adaptation.
In Oulu, climate change -related risks have been evaluated in the Sustainable Energy and Climate Action Plan (SECAP) and city’s climate roadmap. According to them, the most significant risks for Oulu can be divided into three categories:
- Risks related to temperature changes
- Risks related to waters and water management
- Risks related to ecosystem changes
Risks
In Oulu region, both the increase in annual precipitation and the rise in temperatures are causing concern. They can lead to sudden risks due to the increasing occurrence of extreme weather events, as well as to gradually emerging risks. Some of the identified risks are related to the built environment and some to the more natural environment.
The intensification of heavy rains and the increase in the number of rainy days raise the risk of flooding. In the densely built areas, the wide coverage of impermeable surfaces means that the increase in precipitation and especially heavy rains expose the city to flooding. Oulu residents have already experienced the damage caused by stormwater floods originating from thunderstorms and the associated heavy rains. If these risks are not taken into account in the city's urban densification plans, the situation may worsen.
At the same time, it is also necessary to prepare for the opposite extreme, droughts. It is possible that water use restrictions, already in place in many countries, will become more common in Oulu as well.
Drinking water is generally of very high quality in Finland. In the future, the issues with water quality may become more problematic. The amount of chemicals used in purification at water treatment plants has increased significantly in recent years, indicating a deterioration in water quality. Warming and more intense floods can further reduce water quality. In some areas of Oulu, groundwater is used as a source of drinking water. If the occurrence of droughts increases, groundwater may become scarcer than it is now.
The rise in temperatures can increase the number of hot days, which influences the occurrence of heatwaves and the probability of droughts. Elderly people, children, those with chronic illnesses, and those working outdoors or in non-air-conditioned indoor spaces are particularly vulnerable to the adverse effects of higher temperatures. If the daily average temperature stays above 20 degrees Celsius for several weeks, it already poses significant challenges and increases mortality. The warming temperatures during winter, combined with increased instability cause temperatures to fluctuate around zero degrees Celsius. This increases icy conditions, challenging the maintenance of pathways and roads. Accidents caused by slipperiness are expected to increase, which burdens healthcare and affects people's mobility and ability to work.
In addition, the shortening snow-cover season turns our winters darker, which can negatively impact the mental health of Oulu residents. Those suffering from allergies and asthma, and sensitive to pollen, may also witness negative impacts from increasing amounts of pollen in the air. The carbon dioxide concentration in the air increases plants’ reproduction while warming enables the introduction of new species and their pollen in the region.
Solutions
Effective adaptation to climate change requires actions and collaboration across all city sectors. Adaptation must also take into account the interaction between climate change and the biodiversity loss. Climate change influences biodiversity, and conversely, biodiversity loss has effects that exacerbate climate change. Often, the same measures can be used to influence both climate change adaptation and the preservation or improvement of biodiversity.
Greening urban areas is a good example of a measure that has various benefits. For instance, green areas, besides supporting biodiversity, also effectively retain water during rainfall, thus preventing flooding. On the other hand, the evaporation of moisture from them cools the temperatures during heatwaves. It should not be forgotten that green areas also reduce air pollution and increase comfort.
Although densifying urban structures brings many benefits (e.g., shorter travel distances), attention must be paid, for example, to the prevention of stormwater flooding and the so-called urban heat island effect, which occurs also in Oulu. Cities have a lot of asphalt and other impermeable surfaces where stormwater can easily cause damage. These surfaces also heat up efficiently in the sun. Land use planning must allocate enough space for stormwater management structures. The melting snow must primarily be allowed to infiltrate the soil to avoid damaging the quality and quantity of groundwater. Oulu city is striving to increase nature-based solutions for water-absorbing or permeable surfaces, such as green areas and wetlands. The aim is to manage waters in their original location and in this way avoid overloading the sewer system.
Heat radiation and shading, as well as potential cooling needs are emphasized when positioning and orienting new buildings. Cooling needs are also considered during renovations. Primarily, the focus is on increasing structural sun protection and passive cooling opportunities for buildings, such as canopies and plantings. If necessary, cooling systems and air heat pumps are installed.