HomeNews Climate change scenarios will guide Government’s planners
Climate change scenarios will guide Government’s planners
Monday, 24 August 2009
MONRE has issued a set of scenarios for
expected change in sea level, severity of storms and other climate change
events to other ministries, as a first step in ‘mainstreaming’ climate change
assumptions into long-range Government planning.
scenario-building work by the Ministry of Natural Resources and Environment
(MONRE) relies on extensive historical data and the best current estimates by
the Vietnamese and international scientific community. Minister Pham Khoi Nguyen said MONRE will continue to update the
scenarios, especially on sea rise level, so that ministries, sectors and
provinces can take specific actions to limit negative impacts of climate
Deputy Prime Minister Hoang Trung Hai has authorized the
scenarios’ distribution extensively throughout the Vietnamese administration.
Nguyen told reporters that in the last 50 years, Vietnam’s
average temperature increased by 0.5-0.7oC while the sea level rose by 20cm.
Both trends have intensified the impact of storms and floods.
What do the scenarios say?
Vietnam, with large populations concentrated in low-lying delta
regions, is recognized as one of the nations most vulnerable to climate change
– an unsettling fact that has energized government experts and planners.
According to the MONRE scenarios, 90 years from now Vietnam’s
average temperature will be 2.3 degrees Celsius above the average level of the
1980-1999 period. It is forecast that the temperature rise will be
greatest in Vietnam’s
northern half, roughly 2.8 degrees C. Overall, winter
temperatures will rise more rapidly than summer temperatures.
The scenarios also show greater total rainfall, wetter wet
seasons and drier dry seasons, especially in the southern region.
Regarding sea levels, the MONRE experts predict the average
level of Vietnam’s
seas will rise 28-33 cm by the middle of the 21st century and 65-100 cm by the
end of the 21st century as compared with the 1980-1999 period.
Local authorities to define losses caused by climate change
The head of the National Institute for Hydrometeorology and
Environmental Sciences, Tran Thuc, told reporters that these scenarios only
take into account average parameters, because although there is no question
climate change is occurring at an accelerated rate, there’s considerable
uncertainty about its likely extent. The current scenarios don’t provide
detailed judgments about losses caused that are likely to be experienced by
regions and cities that are highly vulnerable to climate change, like the
Mekong Delta and HCMCity.
The scenarios only tell when the sea level rises by 65 or
75 centimeters, how many square kilometers of land in HCMCity
or the Mekong Delta will be flooded. According to Thuc, local governments
can use the data to understand more clearly the likely local impacts. He said
the MONRE will provide local authorities with detailed maps of areas that will
be flooded at different sea rise levels. MONRE will assist the most
vulnerable locations to estimate specific losses caused by climate change and
work out responses that mitigate or adapt to its impact.
The experts who developed the scenarios discovered
noteworthy points in weather and the sea level:
The annual average temperature of the last four decades (1961-2000) was higher
than the annual average level of the three decades ago (1931-1960).
In Hanoi, Da Nang and HCM City, the annual average temperature during the
1991-2000 period was higher than that of the 1931-1940 decade, + 0.8oC for
Hanoi, + 0.4oC for Da Nang and + 0.6oC or HCM City. The trend has
continued into the first decade of the 21st century: in 2007, the
average annual temperature of the three above cities was 0.4-0.5oC above the
average of the 1991-2000 decade.
There have been fewer but sharper cold spells in the past two decades, for
example the prolonged cold snap recorded in the North in January and February
Tropical storms impacting Vietnam
have grown stronger and they have tended to move southwards. The storm season
also ended later, with many storms having abnormal tracks.
Scenarios for sea level
rise, all else being equal:
If the average sea level rises by 65cm, 128 square kilometers of land (6
percent of the total area) will be submerged. The flooded area will increase
to 204 square kilometers (10 percent) if the sea level rises by 75cm and 473
square kilometers (23 percent) in the event of a one meter rise.
2/ The Mekong Delta: If
the sea level is up by 65 cm, up to 5133 square kilometers of land (12.8
percent) will be submerged; at +75 cm, 7580 square kilometers (19
percent). A one-meter rise in the average sea level will inundate 15,116
square kilometers, 37.8 percent of the Delta’s current land area.
Under the various
scenarios, a considerably larger area would be subject to periodic flooding
as a result of storm surges.