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3 August, 2012  ▪  Olena Maksymenko

Less Continental

Global warming is making Ukraine’s climate more oceanic

The apocalyptic projections of some global warming experts are being confirmed by real disasters in Ukraine, such as storms and heavy rains previously unseen. The Ukrainian Week asks Svitlana Boichenko, a Senior Researcher at the Serafim Subbotin Geophysics Institute of Ukraine’s National Academy of Sciences, how climate change will affect Ukraine.

UW: To what extent is climate change brought about by natural or human factors?

There has always been a greenhouse effect in the atmosphere caused by gases such as carbon dioxide, methane, nitrous oxide, tropospheric ozone and others. But humans reinforce the effects of these natural processes as we use fossil fuels. We know this is having an impact because the planet has never seen such swift warming before. We are talking about lengthy periods when the climate system enters warming or cooling phases. Today, we seem to be entering yet another of these little climatic optimums – a period of warming that can last approximately 200-225 years. Yet, the human factor has exacerbated these natural shifts. Nature has contributed just 1/3 of the outcome, while 2/3 of the effect comes from humans. Human impact catalyzes other mechanisms and facilitates natural processes.

For instance, warming is much more intense in the permafrost-covered area of the Northern Hemisphere (the rise in temperature in high latitude areas is 2-30С per 100 years) causing these territories to degrade and become swamps. As a result, swamps release methane, a powerful greenhouse gas. Moreover, the World Ocean can heavily affect the planet’s thermal regime by enhancing or neutralizing the warming. The thing is that a lot of greenhouse gases are dissolved in the ocean and these can be released into the atmosphere as the temperature rises. Aggravated and enhanced by human factors, natural global warming has tilted and catalyzed some natural processes.

UW: How has Ukraine’s climate changed over the past few years?

Global warming drove significant climate change in Ukraine in the 20th century. The planetary temperature rise over the past 100 years was 0.7-0.8°С while Ukraine’s temperature rose by approximately 0.6°С. But Ukraine has some regional disparities in the way temperature changes are distributed across its territory. Northern and North-Eastern Ukraine have experienced the highest temperature rise of 1-1.2°С, while the average rise for the South was 0.3-0.4 and up to 0.5°С. Thus, a kind of leveling of the thermal-climatic field occurred. These are yearly figures. As for seasonal changes, Ukraine has undergone visible warming in winters and slower, if any, changes during summer months. Some weather stations have even noted slight cooling. This is due to either the landscape or the specifics of weather processes. In the general statistics, shifts to extreme temperatures, from long hot periods to long cold periods, are notable.

UW: Are the amounts of rainfall different now, too? Can you say that humidity is rising?

It’s an important factor, especially for agriculture and fresh water. The amount of rainfall has increased slightly throughout the territory of Ukraine over the past 100 years by approximately 5-10%, which is within the random margin of error. Yet, it has changed by region. Northern and northwestern oblasts used to be areas of excessive moisture with swampy parts. Over the past 100 years, the amount of rainfall there has declined by 10-15%. The central part of the country has barely seen any change, while the amount of rainfall has risen by 10-15% in the south and southeast. So, I wouldn’t talk of any significant rise in humidity.

UW: How do these changes affect plants?

They have a positive effect on the whole, but because higher temperatures mean more evaporation, this increased rainfall may not be visible in the southern part of the country as it quickly evaporates into the atmosphere. Research conducted over the course of several years on the Ukrainian steppes by the National Academy of Sciences’ Botanic Institute has shown that moisture loving plants aside from feather grass are expanding in Southern and South-Eastern Ukraine.

Against this backdrop of generally positive developments, extreme precipitation is intensifying, with downpours that are normally typical for mountain areas growing more frequent in arid parts of the country. In fact, other regions also face this trend but it has the most adverse effect in the south and southeast. The Carpathian and Crimean mountain regions are the most vulnerable to such climate change, as well as the Black Sea and the Sea of Azov coastlines because of raised sea levels and human impact on these areas. They also suffer secondary salinization as a result of irrigation and ground sagging as a result of groundwater level changes.  

UW: What impact can all this have on agriculture?

With the pace of warming observed in the 20th century, the change mostly has a positive impact. The human factor increases the amount of carbon dioxide in the atmosphere, which is one of the elements of photosynthesis that “feeds” plants. Experiments in European and American research centers have shown that the doubled amount of CO2 in the atmosphere (to 560–600 mn-1) compared to the pre-industrial era of 1750–1850 enhances the yield of most crops grown agriculturally by almost 15-30% and increases the growth of flora biomass in natural ecosystems. This includes all C3 category plants, including virtually all agricultural varieties, as well as grasses and trees. Moreover, these plants become less vulnerable to temperature and rainfall fluctuations as the amount of CO2 doubles.

UW: What is projected for the near future? Is a change of Ukraine’s climatic zone a realistic scenario?

Based on scenario assessments, the temperature will rise 1.5-2.5 oC if current developments persist. This will not have an extreme impact on Ukraine. Yet, other scenarios suggest a 3-4 oC temperature rise. If that happens, mathematical models and paleoclimate reconstructions project that Southeastern and Eastern Ukraine may become deserts.

Ukrainehas a temperate continental climate. The current warming will bring it closer to an oceanic climate type. Ukraine’s climate is not yet oceanic, but it is growing less continental as the amplitude of seasonal changes evens out. Yet, if pessimistic scenarios prevail and the temperature rises more than 3 °С, the impact may be greater. Models show that southern and southeastern regions will become more arid while northern and northwestern regions will become more humid. These growing contrasts within the territory of Ukraine are unfavourable, yet they are now being mitigated by the current pace of warming.  

UW: Storms have become more common in Ukraine lately. What causes this?

There are several reasons for this. First of all, global warming and the planet’s unbalanced climatic system may cause perturbation and catalyze a slew of dangerous natural processes. But that is not yet a proven fact.

The second scenario is that these storms are accidental. If we look back a thousand years, we see similar disasters mentioned in earlier chronicles.

The third scenario is that we think storms have become more common because they receive constant media coverage now. This is a complex issue and we’ve tried to make some progress on it and draw up some reliable statistics. We looked at records in historical manuscripts and analyzed the evidence preserved in monasteries where monks carefully noted everything. We’ve discovered an interesting effect: warming periods, as well as cooling periods, catalyze several unfavourable phenomena. They only fade in the pauses between temperature rises and falls and maybe that’s what is happening now.

The environmental impact of the warming has been aggravated by ruinous human activity. However, we could still soften some of nature’s damaging processes for ourselves through improvements in agriculture, urban design and the construction of anti-flood dams, among others.

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