The potential impacts of climate change (temperature, wind, duration and frequency of rainfall , and sea level rise) are a major concern in the Mekong Basin.  The consequence of these changes could affect river flow patterns, ecological systems and people’s livelihood which depend directly upon natural resources.

•  a basin wide average temperature increase of 0.79 deg C, with greater increases for colder catchments in the north of the basin (ranges from 0.68 to 0.81deg C)
• an average annual precipitation increase of 200 mm, equivalent to 13.5 percent change, predominantly from increased wet season precipitation, with ranges from -3 to 360 mm
• an increase in dry season precipitation in northern catchments and a decrease in southern catchments, including most of the LMB
•  an increase in total annual runoff of 21 per cent which will mostly occur during the wet season. Pockets of high levels of water stress are expected during the dry season areas such as northeast Thailand and Tonle Sap Great Lake
• an increase in flooding in all parts of the basin, with the greatest impact in downstream catchments on the main­stream of the Mekong River.

These results are based on climate change projections and simulations carried out by ICEM (International Centre for Environmental Management) for the MRC with the General Circulation Models (GCM) using scenarios of the Inter-government Panel on Climate Change (IPCC). Further work is ongoing to better understand impact and improve predictions.  

Change in mean annual precipitation totals comparing the existing situation (1985–2000) with the future (2026–2041) for IPCC emission scenario A2 (high population growth and slower economic growth). Source: MRC (2010a).

References:

MRC (2010a), Impacts of climate change and development on Mekong flow regimes First assessment – 2009, MRC Technical Paper No.29

MRC (2010b), State of the Basin Report 2010.

ICEM (2009), Climate Change Adaptation in the Lower Mekong Basin Countries REGIONAL SYNTHESIS REPORT Prepared by ICEM – International Centre for Environmental Management, 28 March, 2009.