Global warming andSea Level Rise:

Best estimates by 2100

John KingProfessor of Oceanography

Global Warming:What is it?

• The increase in the measured temperature of the earth’s oceans and near-surface air.

Measured temperature increases since 1860

Global annually averaged surface temperatures, based on NASA GISS surface temperature analysis

Global Warming:What’s causing it?

• The increase of these gases causes “The Greenhouse Effect.”

• Human activities add CO2 and other gases to the atmosphere.

Sun’s energy passes through the atmosphere, warming the earth.

Some of the energy is reflected back into space.

Greenhouse gases in the atmosphere trap some of the heat. More gases = more heat.

The Greenhouse Effect

Indicators of human influence on the atmosphere

Changes in Temperature, Sea Level and Northern Hemisphere Snow Cover

Courtesy of IPCC, 2007

Global Warming:Why does it matter?

Global warming causes climate changes that will affect:

• natural ecosystems

• availability of food and water

• global economies

• frequency of extreme weather

events

• human health and lifestyle

Increased CO2 emissions = climate change

Rising Temperatures

Changes in Precipitation

Rising Sea Level

Increasing CO2

Global effects of climate change and sea level rise

Effects of Global Warming:Rising temperatures

Rhode Island climate “migration”

Courtesy of the Union of Concerned Scientists

Rising Temperatures

Courtesy of the Union of Concerned Scientists

Global and Continental Temperature Change

Courtesy of IPCC, 2007

Changes in annual average temperature in the Northeast

Effects of Global Warming:Rising sea level

Four contributions to sea level rise

1. Thermal expansion of seawater

2. Melting of glaciers and ice caps

3. Ice sheet surface mass balance• snowfall - melting

4. Ice sheet surface dynamical imbalance

• increased flow rate

Projected globally averaged surface warming &sea level rise at the end of the 21st century

Courtesy of IPCC, 2007

Sea Level Rise: Observed vs. Projected

Interval Model Prediction Observed

mm/year

1993 - 2003 2.6 3.1

1961 - 2003 1.2 1.8

mm/year

Sea Level Rise: Observed = Projected

observed

projected

2007 - IPCC sea level rise estimate

1. Thermal expansion of seawater .......... 28 cm

2. Glaciers and ice caps ......................... 12 cm

3. Mass balance ..................................... - 3 cm

4. Increased flow ................................... + 3 cm

Total: 40 cm

Range of Estimates: 18-59 cm

ReferenceBy 2100

(feet)Total Rise

(feet)Overpeck,et al., 2006 > 3 13 - 20

Rahmsorf,2007

1.6 - 4.6

- - -

Pfeffer,et al., 2008

2.6 - 6.6

- - -

Sea Level Rise: New Estimates

Reference Additions to global rise predictions

Yin,et al., 2009 + 8 inches

Hu,et al., 2009

+ 12 - 20inches

Total global +regional

2.3 - 8.3feet

Increased sea level rise estimates for New England

Greenhouse Gases in Ice Cores

From Brook, E. J., 2005. Science , 25 vol. 310. no. 5752, pp. 1285 - 1287

Present day

What does 3 feet of sea level rise look like?

Effects of Global Warming:Rising sea level in Rhode Island

Quonochontaug Pond 5’ sea level rise:Model by Nathan Vinhateiro, GSO-URI

Flooded areas shown with light blue shading

Quonochontaug Pond 5’ sea level rise detail:Model by Nathan Vinhateiro, GSO-URI

Flooded areas shown with light blue shading

Quonochontaug Pond 5’ sea level rise detail:Model by Nathan Vinhateiro, GSO-URI

Flooded areas shown with light blue shading

Planning Needs for Rhode Island

1. Seamless digital terrain model LIDAR survey of coastline High-resolution bathymetry of coastal

waters

2. Inundation model Storm surge with wave regime

superimposed Better understanding of coastal erosion

style and rate Expanded Rhode Island sea level and

coastal erosion monitoring program

Possible explanation for why human-induced global warming is still “controversial”