Murari Lal

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AN OVERVIEW OF OBSERVED AND PROJECTED CLIMATE IN
ASIA

• Murari Lal
• Pacific Centre for Environment Sustainable
  Development
• The University of the South Pacific

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NORTH (BOREAL) ASIARussian Federation (50-55N)
- Changes over three recent 30-year periods
suggest a strong warming in winter and spring in
observed data sets (mean annual warming of 2 to
3C). Significantly longer heat wave duration
has been observed in Siberia in recent
decade.During the last 60 years, the annual
mean air temperature in Mongolia has increased by
1.6C. This warming trend started since 1970s and
intensified from the end of 1980s. The warming
has been most pronounced in winter when
temperatures have increased by 3.6C.
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While winter temperatures have risen through out
in Mongolia, this increase have been fastest in
cold climate regions such as high mountain areas
(warming of gt 2C). The spring-autumn
temperature has risen by 1.4-1.5C. Increases
in summer air temperature have ranged from 0.04C
to 2.3C, and are more intense in central
Mongolia but less intense in the western and
eastern parts. No increasing trend in summer
temperature was not observed in the Gobi desert
region.
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Western Russia has experienced a significant
increase in most indicators of heavy
precipitation events while Siberia has a decrease
in the frequency and/or the severity of heavy
precipitation events in recent decades of
observed data. However, most of the
precipitation indicators exhibit a significant
upward trend in their annual anomalies over the
region. The number of days with greater than 10mm
shows coherent patterns of a positive change over
Russia.  
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In Mongolia, normalized anomalies of annual mean
precipitation for 1940-2001 period exhibit a
statistically insignificant decreasing trend for
the country as a whole. During the last 30
year, the annual precipitation has, however,
marginally increased by 3.6 mm/year with summer
precipitation increasing by 5.5 mm/year and
winter by 1.3 mm/year.
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Future ProjectionsAs against the average rate
of global process, the northeast Russia will have
a delayed response to global warming but by 2050,
the air temperature is expected to increase by 3
to 4C and as a consequence-(1) Total area of
permafrost will reduce by 12 to 15(2) Arable
area will become 1.5 times larger(3)
productivity in ecosystems of the south tundra to
increase by 0.1 to 0.2 t/ha per year.
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TEMPERATE ASIAPronounced warming is observed in
the entire country in winter, spring, and autumn,
particularly in the northern part of China since
1959. The frequency of heat waves has become
more in southern China in the recent decade.
 The frequency of cold days in northern China
has reduced significantly.  Mean maximum
temperatures display no statistically significant
trend for China as a whole. The Daily
Temperature Range is decreasing widely. Extreme
minima have also risen, especially in autumn and
winter. The number of frost days exhibits a
significant decreasing trend.
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The trend of the ten highest values in a year of
daily maximum temperatures at all observation
points in Japan shows 1 to 2oC increases in the
past 20 years. There has been a distinct
seasonal shifting as the length of winter season
are shorter while that of summer and spring is
longer during the 1990s over the Korean
Peninsula. In South Korea, the annual mean
temperature has an upward trend at a rate of
0.23C per decade in the past four to five
decades. Climatic extremes have increased here
during recent decades.The diurnal temperature
range in South Korea has increased (except for
summer) as a result of a faster increase in
maximum temperature than in minimum temperature.
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The main characteristic of summer precipitation
in China is a drying trend in the north and a
wetting trend in the central part. Annual total
precipitation has significantly decreased over
the southern Northeast China, North China, and
over the Sichuan Basin but significantly
increased in western China, the Yangtze River
valley and the southeastern coast.  The number
of rain days has significantly decreased
throughout most parts of China with northwest
China being an exception. Meanwhile,
precipitation intensity has significantly
increased. Over the regions with increasing
precipitation trends, there have been much higher
than normal frequency of precipitation extreme
events.
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There has been a systematic increase in the 90th
percentile of daily minimum temperatures
throughout over Korea. This increase is
accompanied by a similar reduction in the number
of frost days and a significant lengthening of
the thermal growing season. The regional trends
of number of Consecutive Dry Days suggest
significant increase while Simple Daily Intensive
Index and fraction of annual total precipitation
due to events exceeding the 1961-1990 95th
percentile have insignificantly increased. This
suggests that the southern parts of Korea might
experience more extreme events in future.
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An analysis of trends of climate indices (annual
precipitation, rainy days, intensity and
frequency of extreme rainfall) during 1961-2000
at more than 120 station in Japan suggested
regionally coherent trends such that the annual
mean precipitation as well as the intensity and
frequency of extreme rainfall have increased in
areas on the eastern side of the Japanese Alps
but decreased along western side in recent years.
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Future ProjectionsTemperate Asia is projected
to experience warmer and wetter climate in the
21st century. Area-averaged temperature changes
for three 30-year periods of 2020s, 2050s, and
2080s simulated under SRES A2 scenario ensembles
are 1.2, 2.5, and 4.1ºC.For rainfall, areas of
larger inter-model variability are in accord with
those of stronger climate change. The
inter-model variability (noise) in precipitation
changes is as large as that of ensemble mean
(signal).
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TIBETAN PLATEAU

• Temperature records for the period 1971-2000
  suggest-
• warming tendency
• Annual mean surface air temperature is 3.4?
• Annual mean increasing trend is 0.024?
• Spatial difference is ranging from -0.069 to
  0.11? on annual mean basis

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• Precipitation (1971-2000) also has
• An increasing trend
• Area-averaged precipitation is 482.8mm
• Mean increasing trend is 1.2mm per year
• Spatial difference ranging from -5.8 to 8.5mm on
  annual mean basis

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Surface temperature has increased at 96 of the
stations Precipitation has increased at 69 of
the stations
Tibet Plateau has an area of 2.5 million km2
stretched to 2,700 km (E-W) and 1,400 km (N-S)
with an average altitude of over 4,000 m.
Temperature
Precipitation
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SOUTH ASIA Increasing trends in annual mean
surface air temperatures have been found over
most of the meteorological stations in South
Asia. In India, the analysis of seasonal and
annual surface air temperatures for the period
1881-2001 shows a significant annual mean warming
of 0.68oC per hundred years. On a decadal
basis, increasing trends in annual mean surface
air temperatures are pronounced since 1970
onwards. The warming is most pronounced during
the post-monsoon and winter seasons. The
monsoon temperatures do not exhibit a significant
trend in most part of the country except for a
significant negative trend over Northwest India.
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Observed Rainfall Variability in India
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The correlation between SMR and food grain
production (FGP) in India (0.71) is significant
at the 1 level. The SMR is responsible for 50
of the variability in total FGP anomalies. It
has a high correlation (r 0.80) with Kharif
food grain production and a moderate correlation
(r 0.41) with Rabi food grain production
anomalies.
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A relatively more pronounced trend in maximum
daytime temperatures has been found compared to
that in the minimum night time temperatures.
Increasing trends in surface air temperature
recorded at several observatories in Pakistan,
Nepal, Bhutan and Bangladesh have also been
reported. The rainfall fluctuations in India as
also in other south Asian Countries have been
largely random over a century, with no systematic
change detectable on either annual or seasonal
scale. However, the linear trends of monsoon
rainfall during 1871-2002 at each of over 200
observing stations across India show
statistically significant trends in some broad
contiguous areas.
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Analysis of summer time surface air temperatures
using data from 1901 to 2003 has revealed that
extremely hot days and the occurrence of
multiple-day heat wave conditions have increased
significantly at selected stations in India
during the past decade. The frequency of
extreme weather events in India for example,
droughts, heat waves, and floods has increased
over the past two decades. For example, the State
of Orissa has been reeling under contrasting
extreme weather conditions for more than a
decade from heat waves to cyclones and from
droughts to floods. Since 1965, calamities are
not only becoming more frequent but striking
areas that never had a vulnerability record.
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Spatial Distribution of Maximum Temperature
Trends in Nepal
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Temperature Changes vs. Altitude
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Comparison with Regional Trend
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Precipitation in Nepal India
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Intense rainfall events have become more frequent
in recent years in many parts of India, Nepal and
Bangladesh.Observational records suggest that,
while the sea surface temperature over the Bay of
Bengal has risen since 1951, the numbers of
monsoon depressions and tropical cyclones forming
over the Bay of Bengal and Arabian Sea exhibit
declining trend since 1970. However, the
intensity of tropical cyclones in Bay of Bengal
seems to have increased in recent past. The
observed trends in the mean sea level along the
Indian coast indicate a rising trend of about 1
cm per decade.
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Glaciers Mass-balance

Rika Samba Glacier, Dhaulagiri
1974
1994
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Shrinking of AX010 Glacier Extent
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Retreat of AX010 Glacier
0.6
60
Area
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Retreat
0.55
40
2
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Area, km
0.5
Retreat, m
20
10
0.45
0
0.4
-10
1976
1980
1984
1988
1992
1996
2000
Year
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Lirung Glacier
1986
The lower part (debris covered) is detached from
the upper part. The debris covered part is just a
mass of dead ice, which is degrading rapidly.
Surface lowering and terminus retreat is fast.
There is a pond in front of the glacier.
2002
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Khimshung Glacier
1985
2002
This small clean glacier near Lirung glacier has
shrunk tremendously in past 17 years
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Glacier Retreat in Nepal

• AX 010 This small glacier is shrinking at an
  alarming rate. If it continues to shrink at the
  same rate it will disappear by 2060.
• Rika Samba The terminus of this glacier is
  retreating by 10 m per year
• Other glaciers in Hidden Valley, Dhaulagiri
  Region are also retreating at the rate of 1.5 to
  3 m per year
• Lirung About 4 m of surface lowering in one year
• Khumbu In this large debris covered glacier the
  surface lowering between 1978 and 1995 was 10 to
  30 m (max 2 m/yr). This glacier might divide into
  two at 5000 m
• Majority of glaciers in Kanchenjunga area are
  also retreating.

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Consequences of Glacier Retreat !

• Variations in runoff is related to percentage of
  glaciated area.
• Variability in runoff is inversely proportional
  to percentage of glaciation
• Decrease in the glaciated area will cause extreme
  flow conditions, i.e.., floods and droughts
• Initially the discharge will increase due to
  higher rate of melting, but later it will
  decrease as ice mass is depleted
• Glacier lake formation
• Glacier Lake Outburst Flood (GLOF)

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GCM Estimates for temperature and precipitation
changes in Nepal
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By the end of 21st century, the area-averaged
annual mean surface temperature rise over land
regions of the Indian subcontinent is projected
to be least in B1 scenario and maximum in A2
scenario and will range between 3.5oC and 5.5oC.
During winter, the area-averaged surface
temperature increase over India would be at least
4oC, while during monsoon it may range between
3.0oC and 4.5oC. The projected surface warming
is more pronounced during winter than during
monsoon season. An increase in the 20-year
return values of daily maximum temperature is
possible over Central India where there is a
possibility of decrease in soil moisture content.
Large extreme temperature increases are also
likely over the drier regions of India.
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• Regional Climate Model Simulations
• Background fields from HadCM2 Global Model
• Regional Climate Model HadRM2
• Control Experiment
• 20 years
• CO2 fixed at present day values
• Climate Projections
• Observed increases in CO2 1860-1990
• 1 / year compound increase thereafter
• Model run for 2041-2060

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Validation ofMaximum and Minimum Surface Air
Temperatures for the Present-day Atmosphere
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PRECIPITATION PATTERNSJJAS from GCM and RCM
control climates, and observations
Hadley Centre GCM Hadley Centre RCM
CRU Climatology
mm/day
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RAINFALL CHANGE OVER SOUTH ASIAas simulated by
Regional Climate Model
mm/day
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Simulation ofMonthly Mean Changes inSurface Air
Temperature and Rainfall
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Simulation ofMonthly Mean Changes inSurface Air
Temperature and Rainfall
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Simulation ofExtreme rainfall Events and
Intra-Seasonal Variability in Monsoon Rainfall
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Simulation ofExtreme rainfall Events and
Intra-Seasonal Variability in Monsoon Rainfall
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Spatial Distribution ofProjected Seasonal
Changes in Surface Air Temperature, Rainfall,
Surface Runoff and Soil Moisture
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Appreciable changes are likely in the spatial
pattern of winter as well as summer monsoon
precipitation over land regions of the Indian
subcontinent. A decrease of between 10 and 20
in winter precipitation over most parts of
central India is simulated for 2050s. During
monsoon season, the results suggest an increase
of 30 or more in precipitation over northwest
India by 2050s. The western semi-arid margins
of Indian subcontinent could receive higher than
normal rainfall in a warmer atmosphere.
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The projected changes in hydrological parameters
over South Asia (apart from rising surface air
temperatures and carbon dioxide) would have
considerable direct effects (on crop physiology)
and indirect effects (changes in pest population
dynamics, irrigation availability, soil
fertility, socio-economic changes) on the crop
productivity in the region.Enhanced variability
in rainfall (already being experienced) will
continue to affect strategic grain supplies and
food security of many nations in South Asia.
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SOUTH EAST ASIA In Southeast Asia, significant
increases were detected in the annual number of
hot days and warm nights, with significant
decreases in the annual number of cool days and
cold nights. These trends in extreme temperatures
showed considerable consistency across the
region. Extreme rainfall trends were generally
less spatially coherent than were those for
extreme temperature. The number of rain days
(with at least 2 mm of rain) has decreased
significantly throughout Southeast Asia.The
proportion of annual rainfall from extreme events
has increased at a majority of stations. The
frequency of extreme rainfall events has declined
at most stations (but not significantly).
Trends in the average intensity of the wettest
rainfall events each year were generally weak and
not significant.
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Under changing climate, Indonesian mean annual
temperature is projected to increase at a rate of
about 0.34oC per decade for SRES-A2 and about
0.21oC per decade for SRES-B2 scenario. The
changes in rainfall vary among models and between
the scenarios. The CCSR and CSIRO models suggest
that the seasonal rainfall would increase
consistently in the period between 2020 and 2080
under both scenarios, except for SON (Sept.-Nov.)
rainfall. However, ECHAM4 and CGCM1 model
simulations suggest that the rainfall would
decrease consistently. In HadCM3 model
projections, the change in rainfall was not
consistent. For example, it suggested that the
DJF (Dec-Feb) rainfall might not change up to
2020s, it would increase up to 2.5 from the
baseline during 2050s and then again decrease to
2 from the baseline in 2080s.
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CONCLUSIONS - KEY POINTS 1. Warming trends
observed all across Asia.2. A decrease in number
of frost days dominates over Asian part of
Russia, Mongolia and China with high percentage
of statistically significant tendencies in the
observed data.3. Increasing trends in heat wave
duration prevails over Russia, northern China,
Japan and India. In most instances they are
statistically significant. 4. Virtually no
consistent significant trends are noticed in the
number of days with precipitation gt10mm in the
rainfall data sets for observing stations across
Asia.
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5. No significant trends are found in total
annual number of days with precipitation of
gt1mm/day in the rainfall data sets for observing
stations across Asia. 6. In general, no
significant trends have been detected in the
fraction of annual total precipitation due to
daily events exceeding the 1961-90 95th
percentile in the areas covered with station data
across Asia.7. Decline in dry period duration
(maximum number of Consecutive Dry Days (with
precipitation less than 0.1mm/day) prevails over
Russia, parts of India and Central and East Asia
(in some instances statistically significant).
Slight statistically non-significant increase
dominates over eastern China.
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