World and Asia climate change: Assessment results by IPCC and Japanese supercomputer model predictions

LA of AR4 WG1 Chapter 5:Observations: Oceanic Climate Change and Sea LevelNational Institute for Environmental StudiesCenter for Global Environmental Research

Yukihiro NOJIRI

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AR4 Publication (Nov.21, 2007)

WG1 The Physical Science Basis, published and pdf available from IPCC web

WG2 Impacts, Adaptation and Vulnerability, pdf available from IPCC web

WG3 Mitigation of Climate Change, pdf available from IPCC web

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5 Lead Authors and 1 Reviewing Editor for the 3 WGs WG1: Y. Nojiri (LA) and contributors WG2: H. Harasawa (CLA), K. Takahashi (LA), S. Nishiok

a (RE) and contributors WG3: M. Kainuma (LA), S. Hashimoto (LA) and contriut

ors NIES research field covers the whole aspect of climate

change sciences We have 4 groups of climate change research; carbon

cycle, satellite observation, modeling, socio-economic study.

NIES Contribution to IPCC AR4

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IPCC Web Page

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AR4 is based on the direct obs. of recent climate change

Since the TAR (3rd assessment report), progress in understanding how climate is changing in space and in time has been gained through:

improvements and extensions of numerous datasets and data analyses

broader geographical coveragebetter understanding of uncertainties,

anda wider variety of measurements

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Global mean temperatures are rising faster with time

100 0.0740.018

50 0.1280.026

Warmest 12 years:1998,2005,2003,2002,2004,200

6, 2001,1997,1995,1999,1990,200

0

Period Rate

Years /decade

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Annual averages of the global mean sea level Averaged global

sea level rise for 1961-2003 is 1.8mm/y.

Rising rate increased to 3.1 mm/y for 1993-2003.

Sea level rise in 20th century is estimated as 0.17m.

Red: reconstructed sea level after 1870Blue: tide gauge observed sea level after 1950Black: sea level based on satellite altimetry

20th century: 1.7±0.5mm/y

1961～ 2003：1.8±0.5mm/y

1993～ 2003：3.1±0.7mm/y

17cm rise in 20th century

Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.

Land precipitation is changing over broad areas

Increases

Decreases

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Global-average radiative forcing estimates and ranges

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Atmospheric CO2 is increasing relating to the fossil fuel emission rate.

Atmospheric oxygen gives constraint for estimating terrestrial and oceanic CO2 sinks.

Atmospheric C isotope change is one of strong evidence of anthropogenic emission.

fossil fuel emission

C isotope change

oxygen/nitrogen ratio

atmospheric CO2

Recent atmospheric CO2 change

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1. How will the world socio-economic conditions develop?

2. How much GHGs will be emitted from the society?

3. How much GHGs will be accumulated in the atmosphere?

4. How will the climate change due to increased atmospheric GHGs?

5. How will the climate change affect human society and ecosystem?

How to project the future?

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How will the climate change due to the increased atmospheric GHGs?

‘Climate Model’ = a climate in a computer

Discretize atmosphere, ocean, land into ‘grids’

Define physical quantities(wind, temp, ..) at each grid

Solve equations of physical principles that govern climate

．．．

cos

1tan

a

pv

a

uf

dt

duF

dt

dp

dt

dTcv

Q

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The “Earth Simulator” ©JAMSTEC

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Climate model and resolution ©JAMSTEC

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Weather chart from JWA

4/18(initial) 4/19(forecast) 4/20(forecast)

4/21(forecast) 4/22(forecast) 4/23(forecast)

Weather forecast is solved from the initial condition, therefore it is impossible to project more than a week or so.

AA

A

B BB

B B

C C CD

16Averaged feature of weather (i.e. climate) not depends on the initial condition, therefore an ensemble run from many initial conditions can represent future climate.

100 yr projection of Japanese Jan. temperature from 3 initial conditions

The difference of initial conditions give different inter-annualvariability, however, the trend (e.g. 100 year average of temperature increase) is very simillar.

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Why the prediction of temperature rise (climate sensitivity) is difficult?

Radiativeforcing

Changes invapor, snow-ice,cloud …

Feedback

The magnitude of feedback determinesclimate sensitivity

Cloud feedback is especially uncertain

Temperaturerise

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Not purely derived from physical principles (cloud, rain, radiation,

small-scale mixing, …)↓

Half-empirically represented　 (Source of uncertainty!)

How will the climate change due to the increased atmospheric GHGs?

‘Climate Model’ = a climate in a computer

Descretize atmosphere, ocean, land into ‘grids’

Define physical quantities(wind, temp, ..) at each grid

Solve equations of physical principles that govern climate

．．．

cos

1tan

a

pv

a

uf

dt

duF

dt

dp

dt

dTcv

Q

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Simulated Temperature Change (1950-2100)

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Assessed ranges for surface warming

(IPCC, 2007）

Scenario dependence

Scientific uncertainty

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1. Agriculture2. Water Resources3. Human health

(Infectious diseases and heat stress)

4. Coastal floods (Heavy rainfall and high tide)

5. …

Impacts of Climate Changeon Human Society

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Projections of Future Changes in Climate

There is now higher confidence in projected patterns of warming and other regional-scale features, including changes in wind patterns, precipitation, and some aspects of extremes and of ice.

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Frost days and heat waves

Extreme events like heat wave, draughts or floods are likely to increase in the future climate.

Heat waves may increase globally, especially Mediterranean and Western North America.

Frost days (days of minimum temperature of 0C)

Heat waves (length of the period of days of 5C higher than climatology)

decreasing increasing Winter warming may be more significant

than summer warming.

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Change of precipitation

Extreme events like heat wave, draughts or floods are likely to increase in the future climate.

Precipitation intensity (annual total precipitation/number of wet days)

Dry days (annual maximum of consecutive dry day)

Subtropical to mid latitude area may have increasing chance of draught.

increasingincreasing

Most of the area may have increasing chance of heavy rain fall.

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JAMSTEC/NIES/University of Tokyo Joint Project

Climate Sensitivity of 4C/CO2 doubling, which is within the higher sensitivity group in the participated simulation models for IPCC AR4 comparison

Following simulation results are for A1B scenario

Climate change movies:by Japanese Earth Simulator

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Global temperature increase

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Global precipitation change

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Sea surface temperature increase

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Snow cover decrease

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Projection of 21th century climate change for each continent from IPCC AR4 report

Box 11.1, Figure 1

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Projection for Asian climate change from IPCC AR4 report

Figure 11.8

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Projection for Asian climate change from IPCC AR4 report

Tibet

India

Japan

Central Asia

Siberia

Thailand < global av. T increase

> global av. T increase

Less precipitation

More precipitation

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Projection for Asian climate change from IPCC AR4 report

Figure 11.9

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Robust findings on extreme precipitation and draught from IPCC AR4 report

Box 11.1, Figure 2

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Hotspot of key vulnerabilities in Asia from IPCC AR4 report

Please check the WG2 report!

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Key vulnerabilities in Asia from IPCC AR4 report

Southeast Asia will be vulnerable for Food and fibre, Biodiversity, Coastal ecosystem, Human health and Land degradation by global warming in 21th century

Central Asia is especially vulnerable for Water resource with very high confidence and South Asia for Food and fibre