How warming of only half a degree affects the planet?

    01 Jul 2021

    Climate change is manifested primarily in rising temperatures, which leads to other dangerous consequences: melting glaciers, droughts, floods, and other extreme weather events. Therefore, the global climate target is determined in degrees. The signatories of the Paris Agreement promised to do everything possible to keep the global temperature rise at a level not higher than 2° C from the pre-industrial level (i.e., when the world has not yet begun to actively burn fossil fuels and so strongly affect the climate). Scientists and activists demand that this figure not exceed 1.5 ° C, while now it has already reached around 1° C.

    Let`s check the Ecoaction NGO explanation what means this half a degree.

    When it comes to the temperature outside, we won’t even feel the difference. However, the planet’s climate system is an extremely complex mechanism, the slightest change in which can lead to large-scale changes in all processes. And just as a person feels unwell even with a temperature of 37.1° C, the inhabitants of the planet will experience disastrous consequences even with seemingly insignificant warming. Why?

    First, the rise in global average global temperature is a generalized indicator, and the situation may differ significantly in different months and in different regions. For example, the Arctic is already warming more than the world average by 2° C. And according to PLOS One magazine, if by 2050 the average global temperature rises by 2-3° C, the warmest months in Eastern Europe will be about 6° C hotter. In terms of climate, the capital of Ukraine may become similar to the modern capital of Australia.

    Even now the temperature rise is felt unevenly. The Borys Sreznevsky Central Geophysical Observatory reports that, for example, the spring of 2020 in the capital of Ukraine was 1.4° C warmer than the climatic norm. At the same time, May turned out to be 2.8 ° C colder than it, and March was 5.8° C warmer. That is, even a small change in averages in practice is manifested in more tangible and less predictable weather fluctuations.

    Secondly, as already mentioned, climate is a system of closely related elements and mechanisms, and imbalance in one of them will have consequences for others. For example, warming in the Arctic is causing glaciers to melt more actively, the area of ​​light surfaces that can reflect sunlight is reduced, and even more heat is absorbed by the ocean. Water heating, in turn, disrupts the heat exchange between the ocean and the atmosphere, which will directly affect the weather and the occurrence of extreme weather events.

    The stronger the temperature rises, the more noticeable such changes and the more difficult it is to stop them later. According to the Intergovernmental Panel on Climate Change (IPCC), even raising the global average temperature by 2° C, which is politically acceptable, will do much more harm to the planet than warming by 1.5 ° C. And that’s exactly how.

    More frequent floods

    Rising temperatures affect the frequency and abundance of precipitation. After all, the warmer, the more moisture evaporates from the surfaces, accumulates in the atmosphere, and falls in the rain. In many regions – especially cities, where the natural cover is replaced by asphalt and concrete – the infrastructure is not ready for heavy rains when the day falls almost monthly water level. Mass felling and construction of river floodplains also contribute to the intensification of floods. According to IPCC forecasts, if the temperature rises by 1.5° C, 11% of areas around the world are at risk of river floods. Warming by 2° C will almost double this share – up to 21%.

    Сoral bleaching

    The oceans are able to absorb carbon dioxide from the atmosphere, as well as absorb excess heat. Due to these properties, climate change is not happening as fast as it could, but it significantly affects their condition. The water heats up and becomes more acidic due to carbon dioxide. Such an environment ceases to be favorable for much marine life, which is accustomed to living in other conditions.

    For example, corals. These marine organisms coexist mutually with microscopic algae, which receive nutrients and have bright colors. In a more acidic and warmer environment, algae die, leaving only the “skeletons” of coral. Such discolored corals become more vulnerable to pre-disease destruction.

    A quarter of all oceanic species live in ecosystems that depend on coral reefs, and even some people owe their safety to them. Reefs serve as a natural barrier to large waves, storms, and floods. Thus, the Great Barrier Reef protects the coast of Australia, where 35% of corals have already died due to discoloration. According to IPCC forecasts, if the average global temperature rises by 1.5° C, 70% of all coral reefs in the world are threatened by discoloration, and warming by 2° C will affect almost all – 99%.

    Biodiversity loss

    Climate change is recognized as one of the greatest threats to plants and animals. According to scientists, about a million of their species are threatened with extinction in the near future. This prospect awaits them not only due to climatic disturbances but also due to a complex of various factors: changes in land use, pollution, urbanization, direct extinction by humans or invasive species. However, the same researchers predict that by raising the temperature by 2° C, climate change alone will endanger the existence of 5% of plant and animal species.

    The climate crisis threatens living organisms in different ways: direct destruction during natural disasters, loss of water and food due to droughts, other changes in the environment, and the loss of the environment itself. IPCC predicts that with warming at 1.5° C, 8% of plant species, 4% of vertebrate species, and 6% of insect species worldwide will lose more than half of their territory. Only half a degree difference will double the proportion of such species of plants and vertebrates, and insects – three times.

    More frequent heatwaves

    Raising the average global temperature leads, of course, to hotter weather in some periods. Heatwaves – abnormally hot weather that lasts for several days in a certain area – in the pre-industrial period occurred on average once every 100 days. Now, when the temperature is about a degree higher, they occur 4-5 times a year. With warming at 2° C from the pre-industrial level, such days will be 27 out of 100, i.e., more than three months a year.

    Heatwaves not only cause discomfort but can also be harmful to health, especially for children, the elderly, and people with chronic illnesses. In hot and humid weather, there is also a risk of heatstroke, because the sweat from the skin evaporates worse in such conditions and the body loses the ability to cool down. The IPCC predicts that a warming of 1.5° C will result in almost 700 million people (i.e., one in ten people) experiencing extreme heat waves at least once every 20 years. In a world that will be 2° C hotter, there will be more than 2 billion such people.

    Loss of ice in the Arctic

    The northern hemisphere is warming slightly faster than the southern hemisphere, although both are now experiencing an unprecedented loss of ice. News of melting glaciers or broken ice appears almost every month, which significantly worsens the climate change situation. As already mentioned, the more ice melts, the faster the temperature rises, and the more (that’s right!) the ice melts.

    The length of the ice cover in the Arctic varies depending on the season, but under modern humans, it has never disappeared completely. The ice cap, which has existed at the North Pole for at least 2.6 billion years, is projected to melt completely in just 15. It is thought that this is not so bad, as new shipping routes and resources hidden under polar waters will open up. However, the melting of the Arctic will do more harm than good to the world’s inhabitants: sea levels will rise, currents will change speed or direction, and animals living in the region will lose areas where they hunt or give birth to cubs.

    Of course, the ice in the Arctic will not disappear completely (at least not immediately). Small ice floes will still float in the middle of the ocean, and the largest central mass of ice, which is constantly shrinking, will disappear only in the warmest months and will recover in the colder periods. According to forecasts, warming by 1.5° C could cause a complete loss of the planet’s “ice cap” in September (late Arctic summer) once every 100 years, but if the temperature rises by 2° C, this will happen about once a decade.


    So a small step on the thermometer scale is a big leap into the abyss of the worst and most serious problems for all mankind. And we no longer have time to argue and seek compromises with the environment, which is deteriorating day by day. Even the effects of 1.5° C warming are already a serious danger to us, and our task is to do everything we can to prevent this. And this means systematically changing the policy now: to abandon fossil fuels in energy and transport, to develop energy efficiency, to move to more sustainable agriculture, to preserve and restore ecosystems, to the green industry.

    You may check our author’s explanation of what forest biodiversity is here.

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