The Pacific slope of Peru is greening, say Cambridge researchers – but they don’t like it?

Andes mountain range

We’re told ‘the exact cause or resulting consequences of this greening are not known’, but the media spin says ‘it’s not good news’. The unhealthy obsession with climate gloom and doom in certain quarters has spilled over here. The massive and ongoing greening trend is decribed as ‘a warning sign, like the canary in the mine’ (which of course expires). Really?
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Research led by physicists and geographers at the University of Cambridge has unveiled some large-scale changes in the vegetation in the South American Andes which may have dramatic impact on the environment and ecosystems of the region, says Phys.org.

Analyzing satellite data spanning the past 20 years, the research team based at the Cavendish Laboratory in Cambridge examined how vegetation has been changing along the Pacific coast of Peru and northern Chile.

This area is known for its unique and delicate arid and semi-arid environments.

The analysis revealed that certain areas experienced positive vegetation growth, known as greening, while others displayed negative trends, referred to as browning. Unsurprisingly, the changes in vegetation are influenced by things like farming and urban development or change in land use practices.

But more interestingly this study, published in Remote Sensing, revealed the discovery of a huge section of the West Slope of the Andes undergoing significant greening in the past 20 years. This section, which extends from Northern Peru to Northern Chile, spanning a length of about 2000km, has seen its vegetation growing significantly over time.

This greening trend varies with altitude, with different vegetation types at different elevations.

The research team, consisting of mathematicians, geographers, biologists, and earth scientists, used satellite images from 2000 to 2020 to observe changes in vegetation over time in this area.

They plotted 450 data points and developed a mathematical model to remove artificial variations (such as cloudy days) and seasonality, and used statistical analysis to ensure that they were only analyzing areas with a significant trend.

“It took three years to sort the methodology and the statistical model,” said Hugo Lepage, mathematician at the Cavendish laboratory and first author of the study. “We really needed to bulletproof it to make sure that something was really happening on a massive scale, and it was not just a fluke.”
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The results of this study have far-reaching implications for environmental management and policymaking in the region. Although the exact cause or resulting consequences of this greening are not known, any large change (30-60% index increase) in vegetation will necessarily have an impact on ecosystems and the environment.

“The Pacific slope provides water for two-thirds of the country, and this is where most of the food for Peru is coming from too,” said Barnes. “This rapid change in vegetation, and to water level and ecosystems, will inevitably have an impact on water and agricultural planning management.”

The researchers believe their findings will contribute significantly to the scientific community’s understanding of the complex interactions between climate change and delicate ecosystems in arid and semi-arid environments.

“This is a warning sign, like the canary in the mine. There is nothing we can do to stop changes at such a large scale. But knowing about it will help to plan better for the future,” concluded Lepage.

Full article here.