Global warming and Sea Level Rise: Best estimates by 2100 John King Professor 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? • Human activities add CO2 and other gases to the atmosphere. • The increase of these gases causes “The Greenhouse Effect.”

The Greenhouse Effect Some of the energy is reflected back into space. Greenhouse gases in the atmosphere trap some of the heat. More gases = more heat. Sun’s energy passes through the atmosphere, warming the earth.

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

Changes in Precipitation 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 Thermal expansion of seawater Melting of glaciers and ice caps Ice sheet surface mass balance snowfall - melting 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 mm/year 1993 - 2003 2.6 3.1 1961 - 2003 1.2 1.8

Sea Level Rise: Observed = Projected

2007 - IPCC sea level rise estimate Thermal expansion of seawater .......... 28 cm Glaciers and ice caps ......................... 12 cm Mass balance ..................................... - 3 cm Increased flow ................................... + 3 cm Total: 40 cm Range of Estimates: 18-59 cm

> 3 13 - 20 1.6 - 4.6 - - - 2.6 - 6.6 Sea Level Rise: New Estimates Reference By 2100 (feet) Total Rise Overpeck, et al., 2006 > 3 13 - 20 Rahmsorf, 2007 1.6 - 4.6 - - - Pfeffer, et al., 2008 2.6 - 6.6

Additions to global rise predictions Increased sea level rise estimates for New England Reference Additions to global rise predictions Yin, et al., 2009 + 8 inches Hu, + 12 - 20 inches Total global + regional 2.3 - 8.3 feet

Greenhouse Gases in Ice Cores Present day From Brook, E. J., 2005. Science , 25 vol. 310. no. 5752, pp. 1285 - 1287

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 Seamless digital terrain model LIDAR survey of coastline High-resolution bathymetry of coastal waters 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”