[Report File] More Greenhouse Gases Emit While We Close Our Eyes

The summer of 2020 is the year when we first remember the previous rainy season and subsequent typhoons rather than heat waves.

The damage caused by last year's typhoons and heavy rains alone exceeded 1 trillion won, and this number alone can help you realize the situation last year.

The amount of damage is more than three times that of typhoons and heavy rains that have occurred in the last 10 years.

In fact, last summer (June~August), the temperature was 23.9℃, which was almost the same as 23.7℃ in the normal year.

It is worth not remembering the heat.

If so, has the warming trend been somewhat weakened?

According to a report on the analysis of global climate conditions released by the World Meteorological Organization (WMO) last month, 2020 was one of the three hottest years ever, along with 2016 and 2019.

Compared to the pre-industrial revolution, the global average temperature has risen by 1.2℃, which means that only 0.3℃ remains in the Paris Agreement target.

With many greenhouse gases still being emitted and warming continues, it is unfortunate that it is difficult for humans to accurately predict this warming trend.

Because there are so many different factors that affect the climate, we know everything and are unpredictable.

The topic to be introduced this time is also part of this study.

More carbon dioxide at night

The area of ​​freshwater located inland, such as rivers and streams, accounts for less than 20% of the entire inland.

However, the amount of carbon dioxide emitted is much higher, over 85% of the total.

The emission per unit area of ​​carbon dioxide from rivers or streams is about four times higher than that of the sea.

Of course, the total amount is more seas, but that is why carbon dioxide emitted from rivers and streams is an important factor and cannot be ignored in predicting the climate.

Current climate models also predict future climates by taking these emissions from rivers and streams into account.

However, an overseas research team recently announced the results of a study that the amount of carbon dioxide emitted from rivers and streams was underestimated.

The researchers included rivers such as the Congo and Amazon, while at the same time taking high-resolution measurements to obtain more precise data than before.

All analyzed 57 years of data from 66 locations around the world, and found that the carbon dioxide produced at night had not been calculated so far.

In the meantime, the analysis mainly measured carbon dioxide emissions between 8 am and 4 pm on average.

However, according to a new study, the share of the time of peak emissions during the day was as small as 10%.

This means that most of the time period when carbon dioxide emission is maximized is nighttime.

(According to the

, carbon dioxide is emitted only during the daytime, but the

this

shows that more carbon dioxide is emitted during the night.)

The fact that I overlooked, there are still many things I don't know

Carbon dioxide emitted from rivers and streams differed by region, but on average, the amount emitted at night was about 30% more than that emitted during the day. The biogeochemical process in the river is the main cause of this difference, and it can be easily thought of as the difference between respiration and photosynthesis. In order for plankton in water to gain energy, it must produce organic matter through photosynthesis, but photosynthesis requires light, so photosynthesis occurs mainly during the day. At this time, carbon dioxide is absorbed and oxygen is released. However, because there is no light at night, photosynthesis cannot be performed, and as the rate of respiration increases than during the day, the emission of carbon dioxide increases.

In the end, the emission of carbon dioxide from rivers and streams, which is currently considered in the climate model, has been underestimated. For more accurate climate predictions, these areas of the model need to be improved.

To get out of the climate crisis, Korea has introduced a carbon-neutral 2050, and countries around the world are moving according to their plans in accordance with the climate agreement. With the advancement of science, the use of new and renewable energy is increasing more and more, and it is expected that someday humanity will no longer depend on fossil fuels. However, the advancement of science has led us to reflect on the dark future by uncovering areas we do not know. In addition to the research introduced this time, there are many factors that are still not considered in the climate model. There are many parts currently not covered by science, such as the mechanism of the polar region and the interaction when the frozen soil layer melts. This is why we need to look at these numbers of 1.5℃ and 2℃ placed in front of our eyes more anxiously.

Lluís Gómez-Gener et al., "Global carbon dioxide efflux from rivers enhanced

by high nocturnal emissions", nature Geoscience (2021) 14, 289–294, doi.org/10.1038/s41561-021-00722-3