Global Ecology

Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons

Global Carbon Cycle

Cain, Bowman & Hacker (2014), Fig. 25.3

Boxes = major pools or reservoirs; petagrams (1 Pg = 1015 g)Arrows = fluxes or rates of movement; Pg/yr

Orange arrows = anthropogenic fluxes

Main pools = atmosphere, oceans, land surface (soils &

veg.), rocks & sediments

Terrestrial pool exchanges C with

atmosphere mostly via photosynthesis &

respiration

Post-Industrial Revolution

anthropogenic inputs have dramatically

increased

Global Nitrogen Cycle

Cain, Bowman & Hacker (2014), Fig. 25.7

Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 g)Arrows = fluxes or rates of movement; Tg/yr

Orange arrows = anthropogenic fluxes

Main pool = atmosphere (N2)

Biological fluxes predominate

Human activity has altered the global N

cycle even more than the global C cycle!

Global Phosphorus Cycle

Cain, Bowman & Hacker (2014), Fig. 25.9

Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 g)Arrows = fluxes or rates of movement; Tg/yr

Orange arrows = anthropogenic fluxes

Main pools = terrestrial soils & marine

sediments

Mining releases 4x more P than weathering of rock (apparently not shown)

Eutrophication can result from

anthropogenic oversupply of P or N(e.g., linked to Gulf

“Dead Zone”)

Geochemical fluxes predominate

Global Sulfur Cycle

Cain, Bowman & Hacker (2014), Fig. 25.10

Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 g)Arrows = fluxes or rates of movement; Tg/yr

Orange arrows = anthropogenic fluxes

Main pools = rocks, sediments, ocean

Anthropogenic emissions have

quadrupled since the Industrial Revolution

Atmospheric deposition is a cause

of acid rain

Image from Wikimedia Commons

Global Change

Climate change – a shift of average weather across a region

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

Images from www.thecanadianencyclopedia.com

Eocene on Ellesmere Island, far north Canada

Modern day on Ellesmere Island, far

north Canada

Global Change

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

Climate change – a shift of average weather across a region

Image from www.thecanadianencyclopedia.com

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

Global Change

Climate change – a shift of average weather across a region

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

Global Change

Image from Wikimedia Commons

Climate change – a shift of average weather across a region

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

Global Change

Then relative stability during pre-Industrial Revolution Holocene

Image from Wikimedia Commons

Climate change – a shift of average weather across a region

Image from NOAA

Global Change

Do you recognize this curve?

Image from NOAA

Global Change

Do you recognize this curve?

Keeling curve

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 Wikimedia Commons

Global Change

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

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

Global Change

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)

Global Change

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

Feb. 17, 1993

Feb. 21, 2000

Global Change – Physical Consequences

Global reduction in ice

Photo from Wikimedia Commons; figs. from Wootton et al. (2008) PNAS

Decreasing oceanic pH

Tatoosh Island, Washington

CO2 + H2O H2CO3 (carbonic acid) H+ + HCO3-

(bicarbonate) 2 H+ + CO32- (carbonate)

Global Change – Physical Consequences

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

Global Change – Biotic Consequences

Altered expression of traits (owing to phenotypic plasticity, e.g., phenology)

Range shifts (especially upslope & to higher latitudes)

Adaptation (to changing environment)

Extinctions (when range shifts and adaptation fail to keep pace with

changing environments)

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

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

Global Change – Public Opinion

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 [e.g., CFCs], with the

ultimate objective of their elimination”

Montreal Protocol (1987)

Image from Wikimedia Commons – NASA image of largest Antarctic ozone hole ever recorded

September 2006

Global Change

Has generally been effective![Strong political will]

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)

Global Change

Has NOT been effective![Weak political will]