Planet Earth is warming …

Greenhouse Warming in 21st

Century • Evidence that rising CO2 levels are changing climate

• Fresh water resources

• More intense hurricanes

• Sea level rise

• Loss of ecosystems

• Likely consequences of global warming

• The ocean’s role in the climate system

The Greenhouse Effect

Some of the most compelling evidence for a link between greenhouse gases and temperature has come from ice cores….

Antarctica Greenland

Glaciers act as “tape recorders” that store a year-

by-year account of temperature and

composition of the atmosphere extending

hundreds of thousands years

back in time

290

190 ppm

The link between greenhouse gas concentrations and surface temperatures is indisputable

580

We are here

381

Levitus et al. Science, 2005

…..about 20 times more heat than the atmosphere since 1955

Oceans 14.5 x 1022 J

Atmosphere 0.7 x 1022 J

Most of the extra energy (heat) has been absorbed by the oceans…..

Ocean Circulation: part of Earth’s heating system

Winds and density of seawater drive ocean circulation

Line W

The Atlantic part of the heat-bearing Ocean Conveyor is very important in moderating the northern hemisphere’s wintertime climate.

Line W

The ocean density which drives this heat conveyor can change.

…so that ocean heat is no longer carried so far northward (as in glacial times)

…but if all the Arctic sea ice melts, the ocean conveyor could extend further north and deliver more heat to the Arctic regions.

In either case, a change in this ocean circulation would itself profoundly change Earth’s climate.

We are monitoring this part of the ocean circulation carefully.

Global climate change is not just about temperature….

A snowman’s perspective

It is expected that the planetary water cycle – evaporation / condensation / precipitation and freezing /

melting – will be altered as a result of global warming.

There is ample evidence of it already happening…

Unprecedented warmth of SST in Indian, W. Pacific and Atlantic Oceans is driving shifts in precipitation patterns…

Above normal hurricane season forecast for 2004Above-normal hurricane season forecastTuesday, June 1, 2004 Posted: 1:05 PM EDT (1705 GMT)

(CNN) -- U.S. hurricane forecasters Monday predicted a busy 2004 Atlantic hurricane season based on a trend of above-normal activity during seven of the last nine seasons.

Above-normal hurricane season forecastTuesday, June 1, 2004 Posted: 1:05 PM EDT (1705 GMT)

(CNN) -- U.S. hurricane forecasters Monday predicted a busy 2004 Atlantic hurricane season based on a trend of above-normal activity during seven of the last nine seasons.

NY Times June 8, 2004

Greenland is melting

Ocean warming and melting land ice are causing sea level to rise

Antarctica’s ice shelves are

growing unstable, increasing the

surge of land ice into the ocean

19791979

20002000

NASA Goddard Space Flight Center

Summer Arctic Sea Ice

is shrinking and thinning

Ice - albedo feedback

Projected Arctic sea ice extent changes

Global Warming is changing landscapes

In our Greenhouse Warming world, the destruction of habitats -- upon which entire ecosystems depend -- is truly alarming.

Habitat destruction

The consequences of burning fossil fuels will be among the great challenges we face

in this century

• Fresh water resources

• More intense hurricanes

• Sea level rise

• Loss of ecosystems

Solutions?

• Fundamentally change the ways humans generate and use energy.

• Develop new technologies and make them affordable and universally available

Planet Earth is warming….

… And they lived happily ever after.

Ocean Circulation: part of Earth’s heating system

Winds cause the ocean to circulate