Great global decline in plant growth and cause dry air

Mohammad ALHADDAD

The shortage of atmospheric water vapor has caused the decline of natural plant growth globally over the past two decades, by 59% in plant regions worldwide.

A study published in the August 14 issue of Science Advance revealed that the growing rate of plant growth worldwide in response to rising carbon dioxide levels could be halted due to increased water stress (the difference between water absorption and loss). .

According to a study by Chinese researchers from Sun Yat-sen University in China, global warming can lead to changes in water vapor levels, which in turn can affect plant photosynthesis, a process that supports plant growth.

Water vapor deficit
After studying four sets of global climate data, the researchers found that the decrease was linked to a deficit in atmospheric water vapor pressure, which has increased sharply in more than 53 percent of plant areas since the late 1990s.

The vapor pressure deficit is the difference between the actual amount of water vapor in the air and the point at which air becomes saturated with water vapor.

When this deficit increases, the pores on the leaves of plants - which facilitate gas exchange - come close together, leading to lower photosynthesis.

The study adds that increasing the deficit of steam pressure also leads to faster drying of plants, and therefore can lead to loss of forests due to drought.

According to the latest reports from the Intergovernmental Panel on Climate Change (IPCC), the Earth consumes about 30% of the greenhouse gases emitted by humans, and plants are responsible for most of the carbon in the land.

Results suggest that in the future plants' ability to absorb CO2 may be significantly low.

Climate change
The reason for the deficit is climate change. There has been a reduction in wind speeds over the oceans, which means that water vapor does not easily land on land and can lead to deficits in vegetation.

Increased warming also plays a role. At a certain temperature, the atmosphere can only retain a certain amount of water vapor.

As temperatures on Earth increase, the maximum amount of water vapor in the atmosphere increases, thus increasing the deficit.

The authors used satellite data to monitor how global plant growth rates have changed since the 1990s.

To reach these results, the research team analyzed satellite images and found a significant reduction in global vegetation and plant leaves, which had previously occurred between 1982 and 1998.

They also looked at the width of tree rings, which are commonly used as a measure of growth. After 1998, there was a decrease in average ring width in more than 100 of the 171 locations studied worldwide.

The Panel expects this drought in the atmosphere to continue until the end of the century.