No. 44




How We Changed the Climate

08 December 2021


RiTo No. 44, 2021

When I started to study climatology in 1958, nobody could predict that climate would gather such popularity or become such a threatening force to humankind as it is now.

The second International Year of Geophysics was drawing to a close, and C. D. Keeling had begun measuring carbon dioxide levels on the slope of the extinct Mauna Loa volcano in the Hawaiian Islands. Older people have learned at school that there is 0.03 per cent carbon dioxide in the atmosphere Now that humankind is constantly adding more carbon dioxide, it would be more accurate to write 0.04 per cent in the textbook. Another way of putting it is that the gas content will double. After the article published by Swedish physicist S. Arrhenius in 1895, it has been calculated that it will take place around 2050. At present, other absorbers of at-mospheric radiation are calculated into carbon dioxide equivalents and expressed as CO2 concentrations. Climate warming is no longer discussed just in a narrow circle of researchers, it is spoken of at ever larger forums. Of course, it takes time to conclude international agreements, but we have now reached the point where there is no time for lengthy negotiations, which is also confirmed by the latest IPCC report (2021) and the European Union’s green transition.

The climate changes that result from the rise in air temperature are already ap-parent, and they are the following. The occurrence of thunderstorms in Estonian skies ranged from ten to fifteen thunderstorms per year in 1990–1994, but has in-creased to twenty thunderstorms per year in the last twenty years. 200 years ago, there were 20 storms a year in Estonia, now there are 30–33, according to different sources. In 1891–1950, there were 26 heavy rainfalls (70 mm or more per day) in Es-tonia, but in 1961–2010, during a period of equal duration, there were 45 heavy rainfalls. The difference is nearly two times.

What will happen in the future? Rise of air temperature will continue. It means that the surface water temperature of the Baltic Sea will also rise. The maximum extent of ice on the Baltic Sea has decreased significantly and the duration of ice cover has shortened. Tallinn port was ice-free for three to six winters in previous centuries, 16 winters in the 20th century and already 12 winters in this century. In fact, we have a few decades of serious work ahead of us to mitigate all kinds of con-sequences and to change the way we live. The climate has indeed been always chan-ging, but we can also look at it in another scale. At the western end of the island of Vilsandi, you can find petrified coral. It did not grow in the Baltic Sea, but was born 350 million years ago near the Canary Islands. It is hard for us to comprehend such a scale of time and continental drift, but this is the geological time scale. Another theory is based on the phenomenon that the angle of the Earth’s rotation axis chan-ges from time to time, causing changes in the distribution of solar radiation and the circularity of the Earth’s orbit. This is related to the ice ages. A third possibility for changing the Earth’s climate is the greenhouse gases in the Earth’s atmosphere, which has taken a few hundred years. What do I want to say with this? I want to say that the Riigikogu with its committees is the most suitable place for managing the transition period or the green transition in a much closer cooperation with scientists than it has been done until now.