• EARTH’S CLIMATE• PAST and FUTURE

• SECOND EDITION

• CHAPTER 17• Climatic Changes Since the 1800s

WILLIAM F. RUDDIMAN

© 2008 W. H. Freeman and Company

Major Concepts: warming planet!• Sea level change since 1880

– Source of records– Corrections for isostatic effects– 17 cm rise; 4 cm thermal expansion, 5 cm mountain glaciers, 2 cm Gr +AA

• Surface temperatures since 1900– Complications: reliability of early measurements, urban heat island effect

• 100-3000 m ocean temperature change since 1945– Heat stored is 10X more than in the atmosphere and provides evidence of

persistent warming• Mountain glaciers

– 99% retreated between 1900 and 1980, average retreat over a mile• Ground temperature profiles show clear warming

– Record integrates century-scale warming that has diffused into ground• Satellite measurements

– Arctic sea ice retreating– Greenland thinning, Antarctica more stable– Tropospheric warming agrees with ground measurements

• Natural variability since 1800’s?– Pacific decadal oscillation– North Atlantic Oscillation

What correction needs to be made formost of these records?

Corrected record

Ground T recording stations

Corrected for heat island effect

Mountain glaciers

Important study from 2005!

Once collect temperature profile, model required temperature change at surface with diffusion models

Satellite measurements of Arctic sea ice

Satellite measurements of NH snow cover

Satellite measurements of growing season in Alaska

Satellite measurements of ice sheet thickness important part of climate monitoring

NOAA NCDC

• http://www.ncdc.noaa.gov/faqs/climfaq14.html

Table 17-1 (in cm)

• Ocean thermal expansion +4

• Mountain glaciers +5

• Greenland and Ant. Ice +2

• All factors +11

• Observed sea level rise +17

Short term oscillations?El Nino

Short term oscillations?

Pacific Decadal Oscillation

Short term oscillations?

North Atlantic Oscillation