CLIMATE CHANGE refers to large-scale and long-term changes in weather patterns that can occur at both local and global levels. Climate change can be natural (e.g., ice age cycles lasting 100,000 years) or human-made. To describe contemporary global climate change, climate indicators are monitored, such as air and ocean temperatures, precipitation, wind, sunshine duration, atmospheric composition, cryosphere, ocean acidity, and sea level.
Overview
- The Earth's temperature has increased by nearly 1.3°C compared to the pre-industrial period (Copernicus, 2025).
- In Europe, the most recent five-year average is approximately 2.4°C higher than the pre-industrial level (Copernicus, 2025).
- In Estonia, the last 30 years have been the warmest in measurement history.
- Precipitation in Estonia has increased by 6% compared to the 1961-1990 average.
- The analysis of long-term changes in wind speed in Estonia is complicated by two main factors: the replacement of measuring instruments and changes in the openness of observation sites.
- There have been no significant changes in the average wind direction distribution for the whole year.
- Sunshine hours in Estonia have increased by 5% compared to the 1961-1990 average.
Global warming
- From 1979 to 2024, according to ERA5 data, the global temperature has increased by an average of about 0.2°C per decade, although the rise has not been uniform.
- From 2015 to 2023, the nine warmest years on record globally occurred.
- Averages for later reference periods have increased in Estonia: during the 1961-1990 reference period, the average air temperature was 5.2°C, while during the 1991-2020 period, it was 6.4°C.
- The five warmest documented years in Estonia (2020, 2024, 2015, 2019, 2008) are all within the last 20 years.
- The number of days with temperatures of +30°C or higher in Estonia has increased by 8.9 days over the past 60 years, and the total duration of heatwaves has lengthened by a week.
- The number of days with temperatures of -26°C or lower in Estonia has decreased by 7.7 days, and the total duration of cold waves has shortened by 4.4 days.
According to the IPCC, the climate change that has occurred since the industrial revolution is human-caused and primarily due to the release of greenhouse gases into the atmosphere. To mitigate climate change and reduce greenhouse gas emissions, the Paris Agreement was signed in 2015 with Estonia's participation, aiming to keep the global average temperature rise below 2°C compared to pre-industrial times. This goal also forms the basis of Estonia's climate policy. For more details, see State of Environment: weather and climate (in Estonian).
Figure 1. Five-year sliding averages of near-surface air temperature on Earth compared to the estimated average of the pre-industrial period 1850-1900. The average of the last five years exceeds the pre-industrial level by 1.3°C. Data: ERA5 (C3S/ECMWF), JRA-3Q (JMA), GISTEMPv4 (NASA), HadCRUT5 (Met Office Hadley Centre), NOAAGlobalTempv6 (NOAA), and Berkeley Earth. Graph: C3S/ECMWF
The climate is warming both in Estonia and globally
Estonia's climate is not isolated from the global climate. As seen in the graph, since the late 1980s, there have been overwhelmingly positive temperature anomalies compared to the 1951-2000 average both in Estonia and globally. Anomalies show how much the values deviate from a long-term average, providing a much clearer picture of climate trends than comparing absolute values.
To compare global average temperatures with pre-industrial times and characterize the impact of human activities on climate change, the global pre-industrial average is often referred to, which is conventionally the estimated average of the 1850-1900 period. Compared to this period, the Earth's average surface temperature has increased by approximately 1,3 °C in recent years, with a rise of up to 2,3 °C over European land areas (Copernicus, 2024). In Estonia, continuous air temperature measurements during the pre-industrial reference period 1850-1900 were only carried out in Tartu and Tallinn, where the averages for that period were 4,5 °C and 4,6 °C, respectively. When comparing the annual average temperatures in Tartu for the period 1870-1900 with the most recent reference period 1991-2020, the temperature has increased by nearly 1,8 °C.
Heatwaves
When considering climate warming, it is important to also take into account extreme weather events associated with climate change, such as new temperature records and heatwaves. Extremes occur less frequently than near-average conditions, but their individual impacts can be widespread and even irreversible. In Estonia, the number of hot days has increased compared to the mid-20th century (the graph below shows only the days when the air temperature exceeded 30 °C, but a hot day in Estonia is conventionally defined as starting at 27 °C), as well as the duration of heatwaves (the graph shows periods of at least three days when the temperature exceeded 30 °C).
Air temperature
To describe climate and its changes, long-term averages of weather elements, known as climate normals, are used. These are 30-year average time series agreed upon by countries under the World Meteorological Organization (WMO). These time series are referred to as reference or normal periods. By comparing weather element values with the averages of the normal periods, we can discuss whether the indicators are higher or lower than the climate average. When comparing Estonia's air temperature across different normal periods since 1901, a rise in long-term averages can be observed.
When comparing the monthly temperature norms calculated based on the average of Estonia's 20 main stations over different reference periods from 1961 to 2020, the highest temperature increases are observed during the winter months (meteorological winter is December, January, February). At the same time, temperature variations are the largest in Estonia during the winter. From May to autumn, the contrasts between different reference periods are much smaller: no sharp changes have occurred, although warming has taken place in all months/seasons. In the long term, the temperature in January has risen the most, while compared to the period 1981-2010, the biggest increase in temperature in the last reference period occurred in December (+1.0°C). Changes in spring and summer months are smaller and more uniform, but in autumn, a significantly higher temperature increase is noticeable in September (the difference between the reference periods 1961-1990 and 1991-2020 is +1.1°C).
Precipitation
- The amount of precipitation has increased by 6% compared to the average of the years 1961-1990.
- Winters have become wetter (+21%), while autumns have become drier (-5%).
- The number of days with very heavy rainfall (≥ 20 mm) has somewhat increased.
Although there has been talk of a likely increase in precipitation in Estonia due to climate warming, the data from the most recent reference period does not directly support this. When comparing the average precipitation values from the reference periods 1981-2020, there has been no increase in precipitation levels analogous to the temperature rise in the data from Estonia's 20 main stations: the most recent norm is lower than the previous one. However, precipitation norms have risen by nearly 6% compared to the period 1961-1990.
Duration of sunshine
- The duration of sunshine has increased by 5% compared to the average of the years 1961-1990.
- The largest change is observed in spring (+10%).
When evaluating changes in the duration of sunshine, it must be taken into account that the heliographs used in Estonia before 2003 measured sunshine duration less accurately than the current sensors. As a result, the annual total graphs do not reflect the actual situation very precisely. Therefore, the later increase in sunshine duration is somewhat overestimated. The following graph shows the annual averages and norms of sunshine duration from 1961 to 2023. The graph is based on data from 7 Estonian stations.
Sunshine duration has increased during the spring months. In June, the duration of sunshine has decreased in the long term (precipitation has also increased in June, see above). The increase in sunshine duration in September also corresponds with the decrease in precipitation during September.