Planting Billions of Trees Turned Barren Desert into a Carbon Sink That Lowers CO2

A mixed-species section of the Green Great Wall – Credit: 中国新闻网 CC 3.0. BY

China’s multi-decade long, successful effort to plant a ring of trees around one of the world’s most hostile deserts has sprouted an unexpected benefit to humanity.

Along with protecting the nation’s grasslands and agriculture from the spreading sands of the dismal Taklamakan Desert, the giant ring of trees has turned previous unproductive land into a carbon sink that draws CO2 out of the atmosphere.

It’s thought, and some isolated research has indeed demonstrated, that humans can prevent the worst effects of a rise in average global temperatures by planting trees to absorb more CO2 from the atmosphere.

This strategy has limits, however, when viewed on a global scale. Atmospheric CO2 levels continue to rise, while there is a limit in the amount of land that can be turned over to forests.

One-third of our planet is covered in deserts, where vegetation is sparse or absent, and rainfall is scarce, yet despite their vast acreage they collectively hold less than one-tenth of the world’s carbon stock, or the amount of carbon that is held underground.

A study conducted by NASA and California Technical Institute (Caltech) has used satellite data to demonstrate that the “sea of death” as the Taklamakan Desert was called in antiquity, could be utilized to store carbon and reduce the greenhouse effect.

The Taklamakan Desert. Credit: NASA World Wind 1.4.

Starting in 1978, China’s Three-North Shelter Belt program aimed to plant trees along the borders of the great Taklamakan to stop sandstorms from ruining adjacent pasture and agriculture land. As the world’s single farthest point from any ocean, the Taklamakan is one of the driest and most hostile landscapes on our planet.

The massive Himalayas rise to the south and east, the Pamirs to the southwest, and a pair of mountains known as the Tian Shan and the Altai to the west, leaving landscape completely isolated from moisture.

66 billion trees have been planted by estimates since the start of the Shelter Belt program, which finished in 2024. Monikered the “Green Great Wall,” this incredible increase in greenery has raised average rainfall by several millimeters, resulting in a natural growth of foliage during the wet season that boosts photosynthesis along the tree line, leading to greater degrees of sequestration.

“We found, for the first time, that human-led intervention can effectively enhance carbon sequestration in even the most extreme arid landscapes, demonstrating the potential to transform a desert into a carbon sink and halt desertification,” study co-author Yuk Yung, a professor of planetary science at Caltech and a senior research scientist in NASA’s Jet Propulsion Laboratory, told Live Science in an email.

By precise numbers, it has reduced the average carbon content in the desert air from 416 parts per million to 413 ppm. Parts per million is used as a measurement for the greenhouse effect. Worldwide, the number is 429.3. It was 350 in before the advent of industrialization.If more shelter belt-style tree planting efforts could be used to reclaim desert landscapes, it could open vast areas to absorbing carbon. With little to no vegetation, deserts in their natural state have precious little ability to do so. Planting Billions of Trees Turned Barren Desert into a Carbon Sink That Lowers CO2
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Here’s why you might want to clean your headphones

Whether it’s enjoying a podcast, listening to music or chatting on the phone, many of us spend hours a day using our headphones. One 2017 study of 4,185 Australians showed they used headphones on average 47–88 hours a month.

Health advice about headphones tends to focus on how loud sounds might affect our hearing. For example, to avoid hearing loss, the World Health Organization advises people to keep the volume at below 60% their device’s maximum and to use devices that monitor sound exposure and limit volume.

But apart from sound, what else is going in our ears? Using headphones – particularly in-ear versions such as earbuds – blocks the ear canal and puts the skin in contact with any dirt or bacteria they may be carrying.

Here’s what you need to know about keeping your ears clean and safe.

First, let’s take a look at your ear

Over-ear headphones cover the entire external ear – the elastic cartilage covered by skin that’s shaped to trap soundwaves. In-ear headphones (as well as hearing aids) are shaped to fit and cover the entrance to the external ear canal, which is called the concha.

Sound vibrations travel through the ear canal – which is S-shaped and a few centimetres long – to reach your ear drum.

Deeper parts of the ear canal produce earwax and oils. These help keep your skin healthy, hydrated and less vulnerable to infection.

Tiny hairs in the ear canal also help regulate temperature and keep foreign debris out. These hairs and earwax help trap and move small particles, shed skin and bacteria out of the ear canal.

Earwax is the ear’s self-cleaning method and we only tend to notice it when there’s too much.

Excessive buildup can block your hearing or even clog the mesh of your earpods. But don’t try to dig earwax out of your ears yourself. If you’re concerned, speak to a pharmacist or GP for advice.

How headphones can affect the ear’s bacteria

Healthy ear canals host a range of non-harmful microbes – mainly bacteria, but fungi and viruses too. They compete for space and nutrients, and this diversity makes it trickier for any potential pathogens (disease-causing microorganisms) to take hold.

But wearing headphones (and other in-ear devices such as hearing aids or ear plugs) may upset the balance between “good” and “bad” bacteria.

One 2024 study compared bacteria in the external ear canals of 50 people who used hearing aids and 80 who didn’t. The researchers found hearing-aid users – whose external ear canals are blocked for extended periods – had fewer types of bacteria than those who didn’t.

Another 2025 study looked at how using headphones (including over-ear, in-ear and on-ear) affected fungi and bacteria in the ear canal. It found using headphones was linked to a greater risk of ear infections, especially if people shared them.

This may because wearing headphones – especially in-ear devices – makes the external ear canal hotter and more humid. Trapped moisture is especially likely if you exercise and sweat while wearing headphones.

Higher humidity increases your risk of ear infection and discharge, including pus.

Wearing in-ear devices such as hearing aids or headphones for extended periods can also interfere with the ear’s natural “self-cleaning” function, aided by earwax.

So, what should I do?

Most of us need – or like – to wear headphones in our day-to-day routines. But for good ear health, it’s important to give your ears a break.

Allow your ear canals to “breathe” at different points throughout the day so they’re not constantly blocked and growing humid and hot.

You could also try bone conduction headphones. These don’t block the ear canal, because they transmit sound through your skull directly into the inner ear, without needing to block the ear canal. These can be expensive though. And while they allow our ears to breathe, high-intensity vibrations (high volume) can still damage hearing, so as with all headphones caution is required.

Other tips

Clean your devices regularly

Recommendations range from once a week to daily to after a physical workout.

For example, you can wipe them with a cloth or use a soft-bristled children’s toothbrush dampened with mildly soapy water. Blot dry with a paper towel and allow a few hours of drying before recharging or reuse.

But it’s best to follow your manufacturer’s guidelines. And don’t forget to clean the case and the body of your earbuds too.

Don’t use headphones when sick

If you have an ear infection, avoid using earphones as they may increase the temperature and humidity in your ear and slow recovery.

Watch for symptoms

If your ears become itchy, red or have discharge, stop using in-ear devices and seek medical advice.The Conversation

Rina Wong (Fu), Research Fellow, Health Sciences, Curtin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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