Why might the worrying consequences of melting glaciers suddenly interest Trump?
Amnon Director, Zveta - Science and Environment News Agency
Melting glaciers in the Arctic could create new, shorter maritime trade routes – a possibility some argue is behind his interest. In Greenland of United States President Donald Trump, one of the most well-known climate deniers. Whether this is the rationale behind his intentions or not, there is no doubt that the Arctic has experienced the The fastest and most drastic consequences of the climate crisis. Processes in the Arctic affect not only the region itself, but also the planet in general, and ultimately our lives. The Arctic is warming At twice the speed from the rest of the world and the amount of ice in the Arctic region is constantly decreasing. Even areas that were once considered immune thanks to the thickness of the ice and the freezing weather are now showing signs of weakening. One of the scientific assumptions that has been used until now is that the melting of sea ice contributes, among other things, For carbon dioxide fixation In seawater. New research challenges previous hypotheses and suggests the opposite (and pessimistic) result.
Carbon pump
In "healthy" oceans, there are a variety of carbon dioxide fixation processes. In such processes, carbon dioxide is "taken" from the atmosphere and stored in the sea - where its climatic and environmental impacts are less. The most important of these is carbon fixation by photosynthetic organisms - most of them microscopic, called microalgae. The microalgae use carbon dioxide and sunlight to create organic matter from which their cells are built. This process is also called the "biological carbon pump" and is an important process for a healthy ocean, since these microalgae also form the basis of the marine food web, meaning that many marine creatures feed on them. The prevailing assumption was that this process contributes to reducing carbon dioxide concentrations in the atmosphere.
Prof. Itay Halevi, from the Department of Earth and Planetary Sciences at the Weizmann Institute of Science, explains that the thaw Glaciers at the poles Causes an increase in the amount of light that penetrates ocean water in areas that were once covered by glaciers. The greater availability of sunlight contributes to an increase in the population of microscopic algae. As the algae become more active, the amount of carbon dioxide they absorb from the atmosphere increases.
study A recently published study presents surprising findings that overturn the conventional hypothesis: the warming of the Arctic Ocean and the accelerated melting of glaciers do not lead to increased absorption of carbon dioxide from the atmosphere, but rather the opposite – they harm the ocean's ability to serve as an effective carbon sink.
"The current study has essentially added a new dimension to ocean circulation models," explains Halevi. Ocean circulation models are models that simulate the flow of water in the oceans - from large currents like the Gulf Stream to small eddies. "The new dimension that is taken into account is the effects of warming on microalgae," meaning that the models take into account changes in the rate of microalgae's production processes and their decomposition rate. High temperatures accelerate the decomposition of the organic matter that makes up the microalgae, which causes the renewed release of carbon dioxide back into the water and eventually into the air. "Ultimately, the increased decomposition rate exceeds the rate of carbon dioxide absorption In photosynthesis", so that the Arctic Ocean does not become a more efficient carbon remover, but on the contrary – it emits more carbon into the atmosphere," explains Halevi. This decrease in the efficiency of the biological pump could worsen the situation of an ocean that is already struggling with the effects of the constant increase in greenhouse gases. This undermines one of the important natural mechanisms for regulating the amount of carbon dioxide in the atmosphere, which could lead to a further increase in the concentration of greenhouse gases and exacerbate the climate crisis.
positive feedback
The results of the study highlight how sensitive ecosystems are to environmental changes, and how their responses are sometimes unpredictable – another reminder that the impact of the climate crisis is complex and changing in ways that are still being deciphered. “This study, along with other studies, should definitely worry us,” Halevi notes. “There is a wide range of studies that point to positive feedback processes that amplify climate change. The process presented in the current study is just one of a host of other processes that operate in parallel,” he says.
A positive feedback is a sequence of processes that reinforce themselves. In this example, warming causes microalgae to decompose more quickly, which releases more carbon dioxide into the atmosphere and leads to further warming – thus creating a self-reinforcing cycle. Another example is the thawing of frozen soils: when temperatures rise, the frozen soils thaw at a faster rate, which increases microbial activity in them. “This process releases additional amounts of greenhouse gases, which further exacerbate warming and accelerate the further thawing of the soils,” explains Halevi. “Therefore, to deal with the consequences of melting glaciers, immediate steps must be taken to reduce greenhouse gas emissions into the atmosphere,” he concludes.
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