Climate Change

Photo of glacial retreat on Mount Kilimanjaro (Feb. 1993 to Feb. 2000) from Wikipedia; Map of Africa from www.admin.uio.no

Feb. 17, 1993

Feb. 21, 2000

Image from Wikipedia (see “Climate”)

Temperature

Weather Patterns are Dynamice.g., monthly variation

Image from Wikipedia (see “Climate”)

Precipitation

Weather Patterns are Dynamice.g., monthly variation

Image from Wikipedia (see “Geologic temperature record”)

Climate Change – a shift of average weather across a region

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Image from Wikipedia (see “Geologic temperature record”)

E.g., Eocene temperature was 4 – 6 °C warmer than today

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Images from www.thecanadianencyclopedia.com

Eocene on Ellesmere Island, far north Canada

Modern day on Ellesmere Island, far

north Canada

E.g., Eocene temperature was 4 – 6 °C warmer than today

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Image from www.thecanadianencyclopedia.com

E.g., Eocene seas were 100 - 150 m higher than today

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Image from Wikipedia (see “Geologic temperature record”)

E.g., Milankovitch Cycles –Earth’s changing orbit influences temperature with ~41,000 & ~100,000 yr periodicities

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Image from Wikipedia (see “Geologic temperature record”)

E.g., Pleistocene glacial and inter-glacial periods

Earth’s Climate is also DynamicClimate Change (or Variation) Characterizes Earth’s History

Image from Wikipedia (see “Geologic temperature record”)

E.g., Pleistocene glacial and inter-glacial periods

Natural Climate “Forcing”(Physical processes that influence Earth’s avg. temp.)

Image from Wikipedia (see “Milankovitch cycles”)

Owing to other planets in our solar system, Earth’s orbit varies over long time scales;

e.g., eccentricity varies from 0.005 to 0.058

Hypothetical circular orbit, no eccentricity

Hypothetical orbit with0.5 eccentricity

Natural Climate “Forcing”Orbital

Image from Wikipedia (see “Milankovitch cycles”)

Earth’s axial tilt (obliquity) varies from 22.1° to 24.5°

Natural Climate “Forcing”Orbital

Image from Wikipedia (see “Milankovitch cycles”)

Orbital forcing causes variation in solar heating of the planet (a.k.a. radiative forcing)

Natural Climate “Forcing”Orbital

Image from Wikipedia (see Global Warming)

Natural Climate “Forcing”Radiative

Image from: www.grida.no

Earth’s avg. temp. = 14 °C

(57 °F)

Without the atmosphere’s greenhouse

effect it would be about -18 °C

(-0.4 °F)

Natural Climate “Forcing”Radiative

This isn’t very surprising, since clouds that form from transpired water are absent over wide, treeless rivers & their immediate floodplains

in the Amazon Basin

At regional scales, deforestation leads to drying (and heating), owing primarily to reduced evapotranspiration and

water-holding capacity of soil

Image from: http://earthobservatory.nasa.gov

Anthropogenic Causes of Climate Change

E.g., cities in the Brazilian Amazon are warmer and drier than those areas were before they became urban centers

At regional scales, deforestation leads to drying (and heating), owing primarily to reduced evapotranspiration and

water-holding capacity of soil

These examples are not global, but they demonstrate that humans can alter regional climate patterns

E.g., much of Greece is warmer and drier today because of deforestation in earlier millennia

Anthropogenic Causes of Climate Change

International Panel on Climate Change (IPCC)est. 1988 by the United Nations

Taking all the accumulated evidence into account, anthropogenic increases in greenhouse gases are the principal

causes of modern global warming; i.e., we are experiencing an anthropogenically enhanced

greenhouse effect

Image from Wikipedia (see “Greenhouse gas”)

Anthropogenic Causes of Climate Change

Photo from: www.thegeneralist.co.uk

Al Gore(b. 1948)

45th U. S. Vice President

Shared Nobel Peace Prize (2007) with IPCC

Academy Award (2007) for the documentary film:

An Inconvenient Truth

Anthropogenic Causes of Climate Change

Image from NOAA

The Keeling Curve

Anthropogenic Causes of Climate Change

Image from www.epa.gov

IPCC predictions are for [CO2] by 2100:500 to 1000 ppm;

with concomitant global temperatures 1.1 to 6.4 °C higher

Anthropogenic Causes of Climate Change

Legally binding treaty through 2012 (when ratified by states) intended to enact resolutions from the United Nations’ Framework Convention on Climate

Change (1992) to achieve “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic

interference with the climate system”

Image from Wikipedia (see “Kyoto Protocol”)

Green = signed & ratified

Red = signed, but not ratified

Grey =non-signatory

Kyoto Protocol (1997)

Treaty to enact resolutions from the United Nations’ Vienna Convention on the Protection of the Ozone Layer (1985) to “protect the ozone layer by

taking precautionary measures to control equitably total global emissions of substances that deplete it, with the ultimate objective of their elimination”

Montreal Protocol (1987)

Image from Wikipedia (see “Ozone depletion”) – NASA image of largest Antarctic ozone hole ever recorded

September 2006

Image from Wikipedia (see “Global Warming”)

Declining Glacial Thickness

Photo of glacial retreat on Mount Kilimanjaro (Feb. 1993 to Feb. 2000) from Wikipedia; Map of Africa from www.admin.uio.no

Glacial retreat (loss) on Mt. Kilimanjaro

Feb. 17, 1993

Feb. 21, 2000

Glacial retreat (loss) in the Alps

Photo by K. Harms – looking down the glacial valley below Lämmerenhütte; Switzerland, October 2010

Glacial retreat (loss) in the Alps

Photo by K. Harms – looking up the glacial valley below Lämmerenhütte; Switzerland, October 2010

Glacial retreat (loss) in the Alps

Photo by K. Harms of Lämmerenhütte; Switzerland, October 2010

Glacial retreat (loss) in the Alps

Photo by K. Harms – the remnant glacier above Lämmerenhütte; Switzerland, October 2010

Photo from Wikipedia; figures from Wootton et al. 2008 Proceedings of the National Academy of Science

Decreasing oceanic pH

Tatoosh Island, Washington

Altered expression of traits (owing to phenotypic plasticity;

e.g., phenology)

Range shifts (especially upslope and to higher latitudes)

Adaptation (to changing environment)

Extinctions (when range shifts and adaptation fail tokeep pace with changing environments)

Climate Change Impacts Biota

Range map and image of polar bear (Ursus maritimus) from Wikipedia

Climate Change Impacts Biota

From Doran & Zimmerman (2009) Eos (formerly Transactions of the American Geophysical Union)

Opinions on Climate Change

Do you think human activity is a significant contributing factor in changing mean global temperature?