Changing Climate and Asian Monsoon

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Changing Climate and Asian Monsoon
Rupa Kumar Kolli Chief, World Climate
Applications CLIPS Div. World Climate Programme
Department World Meteorological
Organization Geneva, Switzerland
Permanent Affiliation Indian Institute of
Tropical Meteorology, Pune
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Thanks to

• IPCC WG1 AR4 Team
• B. Nyenzi, A. Delju, L. Malone, WMO
• J. Revadekar, D. Kothawale, K. Kamala, S.
  Patwardhan, N. Deshpande, P. Kumar, A. Sahai, K.
  Krishna Kumar, IITM
• R. Ashrit, NCMRWF
• H. Douville, CNRM, Meteo France

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Outline

• Introduction
• WMOs Role in Climate Issues
• IPCC WG1 AR4 Highlights
• Climate Change and Indian Monsoon
• Regional Climate Change Scenarios
• Concluding Remarks

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South Asia Population Pressure on Resources

• Total land area 3 of global
• Population (present) 21 of global
• Population (projected-2025) 24 of global

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Asian Monsoon in a Changing World

• We know the earths atmosphere is undergoing
  unprecedented warming
• How does the monsoon behave in a warmer
  atmosphere-ocean coupled system ?
• More atmospheric moisture ? More intense
  hydrological cycle ? More intense monsoon ?
• More intense/frequent ENSO anomalies ? More
  monsoon variability ?
• Which are the sub-regions likely to be affected ?
• Are land-use and land-cover changes associated
  with monsoon changes ?
• How do we distinguish between natural and
  anthropogenic changes in monsoon patterns ?

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How monsoon can change

• Perceptible changes in spatio-temporal patterns
  of rainfall
• More/less frequent years of extreme seasonal
  anomalies
• Late/early onset/withdrawal of the monsoon
• Prolonged or shortened break-monsoon periods
• More/less frequent occurrences of heavy
  rainstorms
• Changes in teleconnections (e.g., weakening of El
  Niño impact)
• Changes in the predictability of monsoon

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Modelling Monsoon Changes

• Climate models are the best tools available to
  estimate future changes in the climatic
  components in a physically consistent manner.
• Atmosphere-Ocean coupled models have made rapid
  strides over the past decade.
• Global models are relatively better in
  reproducing large-scale monsoon features, but
  problems with regional details are yet to be
  overcome.
• Human behaviour being the most unpredictable
  forcing factor for climate change, models can
  only be used for policy guidance, and NOT to
  PREDICT future changes.
• It is essential to appreciate and understand the
  model strengths as well as the associated
  uncertainties to use the results in a
  policy-relevant perspective.

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WMOs historical role in Climate Change

• 1976 First authoritative statement on the
  accumulation of carbon dioxide in the atmosphere
  and the potential climate impacts.
• 1979 First World Climate Conference.
• 1980 Establishment of World Climate Programme
  (WCP) and World Climate Research Programme
  (WCRP).
• 1988 Establishment of the Intergovernmental
  Panel on Climate Change (IPCC).
• 1990 Second World Climate Conference called for
  the establishment of a climate convention.
• Led to the development of the UN Framework
  Convention on Climate Change (UNFCCC) in 1992
• Establishment of the Global Climate Observing
  System (GCOS).

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Integrated framework of WMOs climate activities
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Emerging Opportunities Towards Improved Societal
Response and Sustainable Development

• Relevant climate information is expected to
  enhance policy and decision-making
• Climate data products
• Climate analysis and monitoring capabilities
• Specialized climate forecast products Must
  become user centric
• Climate risk modelling tools Critical for
  decision making
• Disaster Risk Reduction Early Warning Systems
• There is significant diversity in supply and
  demand of climate information at national level
• Needs, requirements and capabilities of providers
• Needs and requirements of the users related to
  policy and decision-making

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Climate Application

• Climate information used for more than just
  curiosity value
• Climate information that influences decision
  making
• Climate information that is effectively converted
  into climate knowledge
• Unless the information provided positively
  influences at least one decision it has NO VALUE

Thanks to Holger Meinke
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Climate Information and Prediction Services
(CLIPS)

• The term climate services refers to the
  delivery of climate information and predictions
  from the scientific sources to end-users
• A service is a service only when it is used our
  goal is to make people use climate services in
  real-world context
• Climate information is just one of the elements
  in the decision making matrix
• Databases of information gathered over many
  years National Meteorological and Hydrological
  Services have great potential to exploit these
  resources to provide effective climate services.

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WMO proactively pursues climate applications

• Espoo Conference (Living with Climate Variability
  and Change July, 2006) highlights the role of
  users and decision makers in climate services.
• Madrid Conference (Socio-economic Benefits of
  Meteorological Services March, 2007) highlights
  the quantification of socio-economic benefits of
  meteorological services.
• World Climate Conference Three being planned in
  October 2009 (Seasonal to Interannual and
  Decadal Climate Prediction)
• Based on a formal statement issued for the first
  time at the UNFCCC COP-12 in 2006, the role of
  WMO and NMHSs has been officially recognized in
  the Nairobi Programme of Work on Impacts,
  Vulnerability and Adaptation to Climate Change.

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IPCC Assessments of Climate Change

• 3 Working Groups
• WG1 Scientific Basis
• WG2 Impacts, Adaptation and Vulnerability
• WG3 Mitigation
• Hundreds of scientists spread across the world
  participate.
• Analyses of a large number of new models and new
  scenarios.
• Policy-relevant but not policy-prescriptive
  assessment.
• Systematic peer review and Governmental review.
• Fourth Assessment Report in the process of being
  released Summary for Policy Makers for WG1 and
  WG2 already released.

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UNFCCC Precautionary Principle

• The UNFCCCs precautionary principle implies that
  activities that threaten serious or irreversible
  damage can be restricted or even prohibited
  before there is absolute certainty about their
  effects.
• Indeed, under Article 3, the Convention calls for
  precautionary measures to combat climate change
  even if there is a lack of full scientific
  certainty regarding a cause effect
  relationship.
• This precautionary principle is considered to be
  a very momentous development in terms of
  international law as well as environmental
  activism

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Direct Observations of Recent Climate Change
Source IPCC AR4 (WG1)
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Direct Observations of Recent Climate Change

• Global average air temperature warming trend has
  accelerated (see, for example, the 100-year
  linear trends)
• 1906-2005 0.74C
• 1901-2006 0.60C
• Average ocean temperature increased to depths of
  at least 3000 m ocean has absorbed 80 of heat
  added (sea water expansion and sea-level rise)

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Global mean temperatures are rising faster with
time
Period Rate Years ?/decade
Source IPCC AR4 (WG1)
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Land surface temperatures are rising faster than
SSTs
Source IPCC AR4 (WG1)
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Changes in Precipitation, Increased Drought

• Significantly increased precipitation in eastern
  parts of North and South America, northern Europe
  and northern and central Asia.
• The frequency of heavy precipitation events has
  increased over most land areas - consistent with
  warming and increases of atmospheric water vapour
  
• Drying in the Sahel, the Mediterranean, southern
  Africa and parts of southern Asia.
• More intense and longer droughts observed since
  the 1970s, particularly in the tropics and
  subtropics.

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Land precipitation is changing significantly over
broad areas
Smoothed annual anomalies for precipitation ()
over land from 1900 to 2005 other regions are
dominated by variability.
Source IPCC AR4 (WG1)
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Proportion of heavy rainfall events increasing
in most land areas
Regions of disproportionate changes in heavy
(95th) and very heavy (99th) precipitation
Source IPCC AR4 (WG1)
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Attribution
Observations

• Observed changes are
• consistent with expected responses to
  naturalhuman forcings
• inconsistent with alternative explanations (e.g.,
  natural only)

All forcing
Solarvolcanic
Source IPCC AR4 (WG1)
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Understanding and Attributing Climate Change

• Continental warming likely shows a significant
  anthropogenic contribution over the past 50 years

Source IPCC AR4 (WG1)
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Projections of Future Changes in Climate

• Continued greenhouse gas emissions at or above
  current rates would
• cause further warming
• induce many changes in the global climate system
  during the 21st century
• Such changes would very likely be larger than
  those observed during the 20th century.

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Projections of Future Changes in Climate

• Best estimate for low emission scenario (B1) is
  1.8C (likely range is 1.1C to 2.9C), and for
  high emission scenario (A1FI) is 4.0C (likely
  range is 2.4C to 6.4C).
• Broadly consistent with span quoted for SRES in
  TAR, but not directly comparable

Source IPCC AR4 (WG1)
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Projections of Future Changes in Climate

• Projected warming in 21st century expected to be
• greatest over land and at most high northern
  latitudes and
• least over the Southern Ocean and parts of the
  North Atlantic Ocean

Source IPCC AR4 (WG1)
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Projections of Future Changes in Climate

• Precipitation increases very likely in high
  latitudes
• Decreases likely in most subtropical land regions

Source IPCC AR4 (WG1)
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IPCC AR4 Assessment of Monsoon Changes

• An increase in precipitation is projected in the
  Asian monsoon (along with an increase in
  interannual season-averaged precipitation
  variability).
• However, the uncertain role of aerosols in
  general, and carbon aerosols in particular,
  complicates the nature of future projections of
  monsoon precipitation, particularly in the Asian
  monsoon.
• Precipitation in summer is likely to increase in
  northern Asia, East Asia, South Asia and most of
  Southeast Asia.
• Most of the coupled models project a decrease in
  precipitation in DJF (the dry season), and an
  increase during the rest of the year. The median
  change, by the end of the 21st century, is 5 in
  DJF and 11 in JJA.
• Although only 3 of the 21 models project a
  decrease in monsoon precipitation, there is a
  relatively larger spread in the projections.
• There is very likely to be an increase in the
  frequency of intense precipitation events in
  parts of South Asia, and in East Asia.

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Long-term regional trends in Indian summer
rainfall Small significant increasing/decreasing
trends lt /- 0.1/yr
Trend in /100yr
exp. variance
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Long-term Trends in Annual Mean Surface Air
Temperature(C/100 yr)
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Temperature Trends over India
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Sea Surface Temperature Trends in the Indian Ocean
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Changing Frequency of Cyclonic Disturbances
during the Monsoon Season
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Changing ENSO-Monsoon relationship
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Annual Cycles of South Asian Rainfall
Temperature for the 20th century in WCRP CMIP3
simulations
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20th Century Summer Monsoon Precipitation in WCRP
CMIP3 Simulations
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Observed and Model Ensemble Monsoon Rainfall
Climatology(Though some individual model
simulations of monsoon rainfall have strong
biases, the ensemble mean has a reasonable
portrayal of the major observed patterns)
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Precipitation Change Projection for AsiaSRES
A1B (2080-2099) vs. 20C3M (1980-1999)
Source IPCC AR4 (WG1)
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Robust findings on regional climate change for
mean and extreme precipitation, drought and snow
(JJA)
Source IPCC AR4 (WG1)
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AOGCM Scenarios of all-India summer monsoon
rainfall and mean annual surface
temperature(simulations used in IPCC TAR)
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Future Scenarios for Summer Monsoon Rainfall and
Annual Temperature over South Asia under A2
Scenario (High Emissions)based on WCRP CMIP3
Simulations(Anomalies relative to current
period)
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ENSO-Monsoon Correlations Observations
Modelling
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Projected Changes in ENSO-Monsoon
Relationshipsdue to Transient increase in
Greenhouse Gas Concentrations (ECHAM4/OPYC3)
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CNRM-CCM Temporal evolution of the transient
response in the ENSO-monsoon correlation
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Simulated Summer Monsoon Response in CNRM
CCM/AGCM Time Slice experiments (Coupled vs
Forced Experiments)
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Time Slice Experiments

• Time-slice experiments reproduce the qualitative
  monsoon response of the coupled model, but there
  are substantial differences in the finer details
  of climate change projections, even when the
  oceanic boundary conditions are directly derived
  from a coupled scenario.
• Ocean-atmospheric coupling and high-frequency SST
  feedback and variability seem to have a
  significant impact on the projected monsoon
  response to global warming.
• High-resolution coupled GCM, at least
  incorporating a slab ocean model, is essential to
  regionalize the impact of global warming over the
  Indian subcontinent.
• Tropical Pacific response to global warming seems
  to be a key factor in determining the Indian
  monsoon sensitivity to anthropogenic forcing.

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Joint Indo-UK Programme on Climate Change Impacts
in India (2001-2004)
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GCMs to Regional Adaptive Responses Modelling
Path
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PRECIS Runs at IITM

• Evaluation experiment using LBCs derived from
  ERA-15 (1979-93)
• Several scenario runs of PRECIS performed
  simultaneously on an array of PCs
• Runs (3 ensembles in each experiment) already
  completed with LBCs having a length of 30 years
  each, for
• Baseline (1961-90)
• A2 scenario (2071-2100)
• B2 scenario (2071-2100)
• All runs done both with and without the sulphur
  cycle

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Model Orography
HadCM3
PRECIS
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PRECIS captures important regional information on
summer monsoon rainfall missing in its parent GCM
simulations.
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PRECIS Simulations of Present ClimateMean Annual
Cycles of All-India Rainfall and Temperature
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PRECIS Simulations of Future ClimateMean Annual
Cycles of All-India Rainfall and Temperature
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PRECIS Precipitation, A2-Baseline, 2071-2100
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Scenarios for Precipitation Extremes
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PRECIS Projected Change in Rainydays
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MRI/JMA TL959L60 Global Model with 20 km x 20
km resolutionBaseline, 1990s (left)B2
Scenario, 2090s (right)
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CCM3-IBIS Tropical Deforestation Experiment
Up to 20 change in rainfall in deforested
simulation
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Changing Climate.

• We are already witnessing the warming of the
  climate system, termed unequivocal by global
  scientific consensus.
• This is unprecedented in at least the last 1300
  years.
• Most of this warming has been convincingly
  attributed to human influence.
• Future projections of warming and the associated
  regional-scale climate patterns are gaining
  confidence.
• Climate change has significant and varied impacts
  on both natural and human-managed systems.
• Climate information needs to be integrated into
  decision making at all levels for sustainable
  development.

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and the Monsoon

• Observed data indicates that the Indian summer
  monsoon has been stable as a large-scale system
  over the past 200 years
• However, the ongoing global warming has
  unambiguous regional signatures, with
  implications for the monsoon
• Most models project enhanced monsoon
  precipitation in a global warming scenario Large
  uncertainties still persist in future projections
  of monsoon.
• Regional models are quite useful in generating
  more detailed regional information, seem to
  inherit some of the biases seen in the driving
  GCMs.
• The robustness of monsoon projections based on
  time-slice experiments could be constrained by
  the lack of air-sea interactions, particularly in
  the Indian Ocean.
• More work needed to understand local
  manifestations of monsoon changes and the
  possible role of land-surface changes/processes.

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Thank YouFor more informationRKolli_at_wmo.int