Chinese Academy of Sciences releases blue book on forest fire carbon emissions! | Expo Daily

Chinese Academy of Sciences releases blue book on forest fire carbon emissions!

On December 7, 2023, the Chinese Academy of Sciences released the "Blue Book on Forest Fire Carbon Emissions Research (2023)" (hereinafter referred to as the "Blue Book"). The Blue Book was led by the Institute of Applied Ecology, Shenyang, Chinese Academy of Sciences, and co-compiled by the Institute of Earth Environment, Chinese Academy of Sciences, and the Institute of Atmospheric Physics, Chinese Academy of Sciences and other units.

The Blue Book estimates the carbon emissions from the Canadian forest fires that attracted global attention this year: as of October 6, 2023, the burned area of ​​forest fires across Canada has reached 18.4 million hectares, with a cumulative number of more than 6,500 fires.

The carbon dioxide emissions generated have exceeded 1.5 billion tons, which is higher than the total carbon dioxide emissions generated by Canada's forest fires in the past 22 years (1.374 billion tons) and even higher than Japan's carbon dioxide emissions from burning fossil fuels in 2021 (1.067 billion tons).

Currently, hundreds of wildfires are still active across Canada, and carbon dioxide emissions are expected to continue to increase.

The frequent occurrence of extreme forest fires is the main reason for the increase in global forest fire carbon emissions, which has a significant impact on the global climate and environment. However, forest fire carbon emissions have not been included in the current carbon budget assessment system and national emission reduction responsibility mechanism.

How does the human ear locate the location by hearing sounds?

When you hear a sudden sound, you often subconsciously turn your head to look in the direction of the sound. We can use sound to obtain information and avoid danger. Have you ever wondered how our two ears can accurately locate the source of sound in three-dimensional space?

Binaural spatial hearing is the main mechanism for sound localization. Humans have different sensitivities to sounds from different directions. Specifically, we are most sensitive to sound sources on the left and right sides of the body, followed by front and back, and then up and down.

Our ears use two main factors to determine the direction of the sound source: the time difference between the sound reaching the two ears and the sound level difference. If the sound source is centered on the left and right but different up and down, then the time it takes for the sound to reach the left and right ears should be the same, and the volume should also be the same. We cannot use the time difference and sound level difference to distinguish the direction of the sound. So how do humans locate the front, back, up and down sound sources?

This is thanks to another important sound localization mechanism - the auricle effect. The shape of the human auricle is an irregular long oval with many protrusions and depressions of various shapes. In this way, after the sound waves from different directions are reflected by the auricle, the reflected sound groups produced will have slight differences in time and intensity. Because the human ear is long and oval, the delay of the reflected sound group produced by the sound from above will be slightly longer than the delay of the reflected sound group produced by the sound from the horizontal direction. Our brain can use these differences to judge the direction of the sound.

The growth is good! It’s time to harvest vegetables from the space garden!

From the Shenzhou 16 mission to the Shenzhou 17 mission, the "space vegetable garden" has gone through two crews and is now growing well.

The Shenzhou 17 astronaut crew picked fresh vegetables grown in the "space garden" and tasted the fresh and delicious "space vegetables", while also preparing for the cultivation of a new batch of vegetables.

The "space vegetable garden" device used for fruit thinning in space is a newly designed second-generation space plant cultivation device. The biggest feature of the "space vegetable garden" is that it realizes rotation and multi-batch planting.

Previously, during the Shenzhou 11 and Shenzhou 14 missions, many astronauts have experienced the feeling of being "space vegetable farmers" and successfully planted lettuce, wheat, rice and Arabidopsis.

In the future, the "space garden" will not only provide food, oxygen and water for astronauts, but also, as a space experiment platform, will play a role in studying the impact of special environments such as space microgravity on plant growth, development, physiology and biochemistry.

The content is compiled from China Science Popularization Expo Weibo, Science World, and China Manned Space Engineering Office

This article was first published in China Science Expo (kepubolan)

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