The Greater Mekong Subregion is already experiencing the impacts of climate change, and based on the best available information these impacts are only expected to worsen.

How the region decides to respond to climate change will shape the fate of millions of people and the region’s biodiversity in the coming decades.

Some of the factors making countries in the Greater Mekong region extremely vulnerable to climate change:
  • High exposure to severe storms
  • High sensitivity to warmer temperatures and precipitation patterns
  • Large populations living in low-lying and coastal areas
  • Heavy dependence on ecosystems and natural resources
  • Relatively low adaptive capacity of many institutions and communities

Climate change, a threat multiplier in the Greater Mekong region

Climate change is best viewed as an ‘amplifier’ of current environmental threats such as habitat loss, poorly planned infrastructure, and unsustainable natural resource extraction.

These threats weaken ecosystem resilience (the capacity of ecosystems to ‘bounce back’ or recover from disturbances and damage), which makes ecosystems even more vulnerable to climate change—a downward spiral that ultimately has serious consequences for humans too.

Likewise, warmer temperatures, changing rainfall patterns, and other manifestations of climate change directly stress ecosystems, rendering them prone to other human pressures including invasive species, pest outbreaks, fire, and changes in the movement, distribution, and quality of water.

Poorly planned responses to climate change can have negative consequences

The unintended negative consequences of human responses to climate change are also extremely difficult to address. Human responses intended to reduce vulnerability, if not carefully conceived with sufficient geographic scope, may increase vulnerability by degrading ecosystems and increasing the exposure or sensitivity of people. That is why WWF is promoting integrated approaches to addressing climate change.

A cascading effect

Ecosystem deterioration in combination with climate change will have cascading effects, which will negatively affect people. For example, water scarcity (resulting from extreme droughts over successive years) may reduce agricultural productivity, which will lead to food scarcity, unemployment and poverty.

Beyond the acute impact of stronger and more frequent extreme climate-related events, people will also suffer "chronically" from an accelerated degradation of the ecosystems. The region’s poorest people will be disproportionately affected.

How climate change is manifesting itself

Warmer and wetter

Across the Greater Mekong region, temperatures have risen by 0.5 to 1.5 ºC in the past 50 years and continue to rise. More frequent and severe droughts and floods are already causing extensive damage to property and loss of life.

The most recent models suggest continued warming, increased climate variability, and more frequent and damaging extreme weather events such as droughts, floods, and high-intensity tropical storms. Wetter rainy seasons are expected to lead to increased flooding, and drier dry seasons will exacerbate water shortages.

Moreover, the reliability of climate cycles such as the onset of monsoon precipitation may be shifting. These trends are very likely to accelerate and intensify in coming decades as the rate of climate change increases.

Altered precipitation patterns and warmer temperatures will negatively impact the productivity of agriculture and fisheries, threatening food security, and substantially alter the composition and function of the region’s terrestrial and aquatic ecosystems.

Sea level rise

Sea level rise is threatening the region’s coastal communities, adding stress to coastal ecosystems such as mangroves. These have already suffered from large-scale conversion for shrimp and fish aquaculture and for rice cultivation (see Ca Mau and Krabi reports top right of this page).

By the end of the century, higher sea levels in the Mekong Delta, where nearly half of Vietnam’s rice is grown, may inundate about half (~1.4 million ha) of the delta’s agricultural lands and displace millions of people.