Transcript pptx

Global Ecology
Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons
Global Carbon Cycle
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
Cain, Bowman & Hacker (2014), Fig. 25.3
Global Nitrogen Cycle
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!
Cain, Bowman & Hacker (2014), Fig. 25.7
Global Phosphorus Cycle
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
Geochemical fluxes
predominate
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”)
Cain, Bowman & Hacker (2014), Fig. 25.9
Global Sulfur Cycle
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
Cain, Bowman & Hacker (2014), Fig. 25.10
Global Change
Climate change – a shift of average weather across a region
E.g., Eocene temperature was 4 – 6 °C warmer than today
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
Eocene on Ellesmere
Island, far north Canada
Images from www.thecanadianencyclopedia.com
Modern day on Ellesmere
Island, far north Canada
Global Change
Climate change – a shift of average weather across a region
E.g., Eocene seas were 100 - 150 m higher than today
Image from www.thecanadianencyclopedia.com
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
Image from Wikimedia Commons
Global Change
Climate change – a shift of average weather across a region
E.g., Pleistocene glacial and inter-glacial periods
Then relative stability during pre-Industrial Revolution Holocene
Image from Wikimedia Commons
Global Change
Do you recognize this curve?
Image from NOAA
Global Change
Do you recognize this curve?
Keeling curve
Image from NOAA
Global 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 Wikimedia Commons
Global Change
IPCC predictions are for [CO2] by 2100:
500 to 1000 ppm;
with concomitant global temperatures 1.1 to 6.4 °C higher
Image from www.epa.gov
Global Change
Earth’s avg.
temp. = 14 °C
(57 °F)
Without the
atmosphere’s
greenhouse
effect it would
be about
-18 °C
(-0.4 °F)
Image from: www.grida.no
Global Change – Physical Consequences
Feb. 17, 1993
Global reduction in ice
Feb. 21, 2000
Photo of glacial retreat on Mount Kilimanjaro
(Feb. 1993 to Feb. 2000) from Wikimedia Commons;
Map of Africa from www.admin.uio.no
Global Change – Physical
Consequences
Decreasing oceanic pH
Tatoosh Island,
Washington
CO2 + H2O
H2CO3 (carbonic acid)
H+ + HCO3(bicarbonate)
2 H+ + CO32- (carbonate)
Photo from Wikimedia Commons; figs. from Wootton et al. (2008) PNAS
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)
Range map and image of polar bear (Ursus maritimus) from Wikimedia Commons
Global Change – Public Opinion
Do you think human activity is a significant contributing
factor in changing mean global temperature?
From Doran & Zimmerman (2009) Eos (formerly Transactions of the American Geophysical Union)
Global Change
Montreal Protocol (1987)
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”
September 2006
Image from Wikimedia Commons –
NASA image of largest Antarctic ozone hole ever recorded
Has generally been effective!
[Strong political will]
Global Change
Kyoto Protocol (1997)
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”
Green =
signed & ratified
Red =
signed, but not ratified
Grey =
non-signatory
Image from Wikipedia (see “Kyoto Protocol”)
Has NOT been effective!
[Weak political will]