The ocean absorbs 50% of CO2 emissions

Such chimneys emit many greenhouse gases. About 50% of the total amount of CO2 emitted by humans since the industrial revolution has dissolved into the world's oceans, adversely affecting marine organisms. .

This is the conclusion from two new international studies. In the first study, scientists focused on the amount of CO2 stored in the oceans. They found the world's oceans functioned as a giant sink absorbing greenhouse gases. According to them, the process of removing this gas from the Earth's atmosphere has slowed global warming.

However, in the second related study, the scientists said this "reservoir effect" is currently changing the chemistry of the ocean. That change slows the growth of plankton, corals and other invertebrates - the most fundamental element in the ocean food chain. Impacts on marine life may be very serious.

The amount of CO2 missing

"The oceans are serving humanity by eliminating CO2 from the atmosphere," said Christopher Sabine, geophysicist, at the US Oceanic and Atmospheric Administration. The problem is that this help results in the ecological and biological structure of the oceans. " Sabine is the co-author of both studies.

As a greenhouse gas, CO2 traps solar heat in the Earth's atmosphere. This is the gas that contributes the most to global warming. Since fossil fuels were used strongly around 1800, the concentration of CO2 in the atmosphere has increased from about 280mg / l to 380mg / l. Today's atmospheric CO2 level is only about 50% of what scientists have predicted, based on the estimate that people contribute 244 billion tons of CO2 to the atmosphere each year. According to Sabine, half of the remaining CO2 emissions are absorbed by the ocean or terrestrial plants.

Cement plant on Volga river, Russia. Scientists have long suspected that the ocean is a giant CO2 reservoir. Estimates of how CO2 is accumulating in the world's oceans are based on computer models or other indirect methods. However, in the new study, scientists collected samples directly of the level of CO2 dissolved in oceans around the world during the 1990s. Data were collected at 9,600 points around the world in 95 trips. separate study. This is an effort of two international groups: World Ocean Circulation Experiment (WOCE) and Global Ocean Flow Study (JGOFS).

Using data on Sabine and researchers from the US, Europe, Australia, South Korea, Japan and other countries has completed the most complete survey of ocean chemical structure. The results show that the oceans absorb 48% of the total CO2 emitted from fossil fuel combustion and cement production from 1800 to 1994. It suggests an answer to the question that makes scientists puzzled before: Where did half of the missing CO2 scientists estimate humans emitted into the atmosphere?

Taro Takahashi, a geochemist at Columbia University, said this answer is important for two reasons: first, to help us understand the Earth's natural carbon cycle; secondly, forming a solid strategy to manage CO2 emissions. Sabine, the leader in the first study, said that besides the atmosphere, the world's oceans are the only large repository for the amount of CO2 that people emit over the past two centuries. He notes that most of the previous research focused on the amount of CO2 that plants have absorbed in the past few decades.

Impact of the ocean

According to Sabine and colleagues' research, the amount of CO2 absorbed by the oceans is only 1/3 of the amount it can contain. They recommend: So then global warming can accelerate.

Don't let the ocean "break the belly". In the second study, the scientists found that although the ocean is contributing to reducing global warming, dissolved CO2 in it is affecting harmful marine life. Richard Feely, a marine chemist at the US National Oceanic and Atmospheric Administration, is the second head of research. He said: "Because CO2 is an acid gas, the pH on the sea surface is decreasing. pH is a measure of acidity in solutions ''.

If predicted by Feely's group to be right, the surface of the oceans, where we found most marine life, could soon be more acidic than the last five million years. The increase in acidity causes animals to form shells and some algae can hardly accumulate carbonate ions from seawater to form their calcium carbonate crust. Corals, some mollusks, tiny unicellular organisms (with holes) and coccolithophorid may be affected. Many of these species form important links in the marine food chain.

Past studies have shown that if atmospheric CO2 at 700-800mg / l may occur at the end of this century, shellfish will decrease by 25-45%. And the scientific community has yet to predict the consequences of the decline in the amount of shellfish for the food chain at this time.

Minh Son (According to National Geographic)