London, While climate change and rising global temperatures are leading to decline in vegetation in arid regions of the world's poorest countries, the situation appears to be better in wealthier countries, says a study.

For the study, published in the journal Nature Sustainability, researchers from University of Copenhagen in Denmark followed vegetation trends across the planet's driest areas using satellite imagery from recent decades.

They found that too little vegetation is sprouting up from rainwater in developing nations, whereas things are headed in the opposite direction in wealthier ones.

As a result, the future could see food shortages and growing numbers of climate refugees.

"We observe a clear trend of arid areas developing in a negative direction in the most economically challenged countries," said Professor Rasmus Fensholt from University of Copenhagen.

"Here, it is apparent that the growth of vegetation has become increasingly decoupled from the water resources available and that there is simply less vegetation in relation to the amount of rainfall. The opposite is the case in the wealthiest countries."

According to the researchers, there may be several explanations for the uneven impact of climate change.

Among the most obvious is rapid population growth, in Africa for example, where there is an increasing need to exploit land that is otherwise poorly suited for agriculture.

Doing so produces lower yields and puts increasing amounts of livestock on too little grass in already fragile ecosystems.

Conversely, vegetation in arid areas of the world's wealthier countries seems to be coping better with climate change.

This is likely due to the intensification and expansion of larger farms, where more economic resources allow for, among other things, irrigation and fertilisation.

"Here, our results demonstrate that in arid regions, particularly those in Africa and Asia, less vegetation grows for the amount of rainwater that falls, while more vegetation grows in arid areas of South America and Australia," said lead author Christin Abel from University of Copenhagen.

The results suggest that as a result of climate change, future trends for the planet's poorest areas only seem to be getting worse at a time when more than 40 per cent of Earth's ecosystems are arid.

Forecasts point to an expansion of today's arid areas where they will make up a larger and larger share of our global ecosystems.

This may result in more and more people being left without food and their needing to migrate.

"One consequence of declining vegetation in the world's poorer arid regions areas may be an increase in climate refugees from various African countries," Fensholt said.