Climate change is already reshaping life and landscapes across the world’s longest mountain range which extends the length of South America’s western side, new research has found.

Climate change isn’t just a future threat for the Andes mountain region, but a present reality that is already occurring, found the study, published in the Communications Earth & Environment journal.

An international team of six scientists from four different countries collaborated to compare predictions from climate models with real-world observations of the Andean climate, natural environment, industries and societies.

"We examined evidence that climate change and its impacts are already occurring in the Andes, the world’s longest mountain range, which crosses seven South American nations from Argentina and Chile in the south, through Bolivia, Peru, Ecuador, and Colombia, to Venezuela in the north," says hydrologist Dr Ana Ochoa-Sánchez from Ecuador’s University of Azuay.

"What we found was that human-induced climate change is warming all of the Andes. Climate change is already occurring and noticeably impacting one of the world’s iconic mountain regions. One of the most significant impacts is that climate change is likely causing less precipitation on the eastern side of the mountain range.

"Mountain regions are predicted to be among the most sensitive and vulnerable to human-induced climate change, with changes causing a cascade of impacts across South America," says climate scientist Dr Dáithí Stone, at New Zealand’s National Institute of Water and Atmospheric Research (NIWA).

"Throughout the Andes the climate trends are causing rapid shrinking of glaciers and reduction in the accumulation of snow. This results in reduced water flowing down from the mountains and brings about changes in ecosystems. This in turn, in multiple countries, affects food production, industry, health, culture and societies."

The research will improve understanding of future impacts, and the effectiveness of adaptation, says Dr Stone.

"In order to understand how climate change might affect us in the future, we need to understand how it is already affecting us. As we implement more measures to adapt to climate change, future updates of this study will also be able to evaluate how effective those adaptation measures have been and how they might be made more effective."

The extensive and diverse Andes, which runs from the Caribbean coast to its southern tip in Patagonia, means the study advocates for localised adaptation strategies, informed by scientific research and indigenous knowledge, says Dr Ana Ochoa-Sánchez.

"The research also stresses the need for global climate policies to reduce emissions and increase adaptation to support vulnerable mountain regions, such as our iconic Andes. The findings highlight that climate change is not a distant threat but a current crisis already unfolding across one of the world's most celebrated mountain landscapes."