3,000 km "Green Great Wall"? China's largest desert is surrounded! | Environmental Trumpet

Hello everyone, this is the 24th issue of the Environmental Trumpet column. In this issue, we have collected the following environmental research and news worth reading:

1) 350 African elephants died suddenly because they drank poisonous water?

2) China's largest desert is surrounded by greenery

3) Burying 20,000 tea bags in the soil to measure wetland carbon storage capacity

4) Research has found that young people aged 18 to 35 are more likely to die from heat stroke

5) Switzerland and Italy renegotiate border as glaciers melt

African elephants die en masse.

Was it because he drank poisonous water?

From May to June 2020, 350 African elephants died in Botswana . Botswana is located in Africa. Although it is a small country, it is home to nearly one-third of the African elephants on the earth. Why did the African elephants die so strangely? Recently, a study published in Science of The Total Environment gave the answer - they drank toxic water and died of poisoning.

Due to the impact of the COVID-19 pandemic, African elephants died en masse, and researchers were able to collect samples for analysis some time later | Amanda Stronza - Ecoexist

Where does the poison in the water come from? Using satellite data, researchers analyzed the location of the dead elephants and the water quality of the water holes. From 2019 to 2020, the water holes near the dead elephants first experienced an extreme drought and then an extremely wet year. The switch from extreme drought to wet weather allowed sediments and nutrients in the water holes to return to the water, promoting the growth of algae and causing frequent algal blooms in the water holes. During the period when the elephants died, the algae levels in the water holes were extremely high, and algal toxins were likely present.

Climate change makes algal blooms more frequent | Tricia McCormack, SCCF environmental policy intern

The African elephants may not have recognized the abnormality in the water and mistakenly drank the poisonous water. The study estimated that the elephants walked an average of about 16.5 kilometers after drinking the water and died within 88 hours. Who would have thought that the chain of climate change would eventually kill African elephants en masse?

China's largest desert is surrounded by greenery

Recently, with the last few desert rose seedlings being planted, China's largest desert, the Taklimakan Desert, was finally surrounded by a sand-blocking protection belt built by generations of people, achieving the "edge locking" of the desert.

Yutian County is famous for its desert roses. Yutian County is an oasis city located on the southern edge of the Taklimakan Desert | Yutian County Media Center

As the second largest desert in the world, the Taklimakan Desert covers an area of ​​337,600 square kilometers. There are many cities around the desert, which have suffered from sandstorms in the past. In order to curb the impact of the desert on cities, people have insisted on planting shelter forests around the desert for more than 40 years and built a 3,046-kilometer-long "Green Great Wall" .

The protective forest belt photographed in Hotan County. The "locking edge" task had not been completed when the photo was taken, but the protective forest stretching forward was already visible. | Ding Lei/Xinhua News Agency

Planting desert plants requires consideration of plant species selection, breeding of high-quality seedlings, and irrigation for seedling growth. People use more than 20 desert plants such as poplar, saxaul, and red willow to build shelterbelts, and use groundwater drip irrigation technology and ecological water replenishment to allow these seedlings to better obtain water and survive the relatively fragile early growth stage.

Who buries 20,000 tea bags in the dirt?

A recent study published in Environmental Science and Technology found that rising temperatures will endanger wetlands' ability to store carbon , and that different wetland types have different sensitivities to climate change. Curiously, the study came to its conclusions using tea bags.

This is a tea bag buried in a salt marsh in Tasmania, Australia | Inger Visby

In the experiment, researchers buried about 19,000 tea bags in 180 wetlands in 28 countries . The tea leaves in the tea bags are organic matter that can be decomposed. Over a three-year period, researchers regularly retrieved the tea bags from various locations, weighed them, and calculated the amount of tea leaves remaining in the tea bags. Simply put, the more tea bags are left, the slower the decomposition of organic matter in the wetland , and the greater the ability to store carbon in the wetland without releasing it.

The tea bags buried in the wetland were of two types: green tea and rooibos. These two types of tea represent two different types of organic matter. Green tea has a high content of water-soluble compounds that decompose quickly, representing unstable organic matter. In contrast, rooibos has a high content of fiber and lignin, which decomposes more slowly, representing more stable organic matter.

Rooibos tea is made from a South African leguminous shrub. It does not contain caffeine and does not become bitter even after long soaking | Thee.be

The study found that temperature does affect how quickly wetlands break down organic matter. As temperatures rose, wetlands broke down rooibos tea faster, but this didn’t matter much for wetland type. In contrast, green tea bags degraded at different rates in different wetlands—freshwater wetlands broke down green tea faster, while mangrove and seagrass wetlands broke it down more slowly. Overall, though, the experiment found that tea bags buried in freshwater wetlands and swamps had the most tea leaves left, suggesting that these ecosystems may have a greater ability to store carbon .

Photographs show researchers retrieving tea bags buried under sea prairie | Peter Davey

The high temperature is actually aimed at young people?

Researchers have found that as the world warms, young people aged 18 to 35 are more likely to die from heat stroke . The research results have been published in Science Advances.

The study focused on residents of Mexico , since not every country collects detailed data on mortality and weather. The researchers focused on excess mortality and wet-bulb thermometer data to try to find a connection.

The analysis found that from 1998 to 2019, about 3,300 people died from heatstroke each year in Mexico. Among them, people aged 18 to 35 accounted for nearly one-third, while the number of deaths from heatstroke was the least among those aged 50 to 70. Moreover, male workers seem to be more susceptible to heatstroke.

Why is this? The study gave the following possibilities. First, it is work. Compared with the elderly, young people are more likely to engage in outdoor and physical labor, which increases the risk of heat stroke and dehydration. Second, young people prefer to participate in outdoor sports , and outdoor sports in high temperatures can also cause heat stroke.

Working in the hot sun | Pixabay

Switzerland and Italy renew border as glaciers melt

Under the influence of global warming, warming in mountainous areas is accelerating. In Europe, the temperature rise in the Alps is even faster than the global average. In recent years, the volume of glacier melt in Switzerland has continued to rise, and in 2022 it broke the previous record, reaching 6% of the total volume.

The melting of glaciers has had an impact on the border between Switzerland and Italy. In the past, part of the border between Switzerland and Italy was divided along a ridge formed by glaciers in the Alps. Today, climate change has caused the ridge to move slightly towards Italy.

Matterhorn, one of the highest peaks in the Alps, has seen its ice and snow melt due to global warming, causing the border to shift | Peters/Flickr

After consultation, the two countries reached an agreement to divide the border according to the changed mountain ridge. In other words, a small part of Italian territory will be assigned to Switzerland in the future . At present, the Swiss government has officially approved the change, and the Italian government is in the process of approving it.

The change of national boundaries will not bring much impact, the biggest risk is the melting of glaciers themselves. Meteorologists point out that the melting of glaciers will bring more extreme disasters to local communities, such as landslides and floods .

References

[1]https://www.kcl.ac.uk/news/satellite-evidence-bolsters-case-that-climate-change-caused-mass-elephant-die-off

[2]https://www.btwmw.net/content/content_1936998.html

[3]https://finance.sina.com.cn/cj/2024-12-04/doc-incyimai3657950.shtml

[4]https://niwa.co.nz/news/spilling-tea-wetlands

[5]https://interestingengineering.com/science/teabags-to-measure-wetland-carbon-storage

[6]https://phys.org/news/2024-12-high-preferentially-young.html

[7]https://news.climate.columbia.edu/2024/12/06/glacier-melt-leads-to-redrawing-of-the-italian-swiss-border/

[8]https://www.bbc.com/news/articles/cgk7r0rrdnmo

Author: Xiao Xiaoze

Edited by: Yellowtail Pollock