Transcript Document

Past Global Changes
• Paleoclimates and environments
of the Nth and Sth Hemisphere
(Pole-Equator-Pole transects)
The ice cap on Kilimanjaro is melting so fast it
may disappear by 2020
• International Marine Global
Changes
• CLIVAR/PAGES Intersection
• Polar Programmes
• Past Ecosystem Processes and
Human-Environment Interactions
Thompson et al (2002)
Responses of the
biophysical Earth System
to the accelerating
’human enterprise’.
The biophysical responses
of the Earth System show
many of the same features
as the Great Acceleration
in the human enterprise.
From: Steffen et al. 2004
Land-Ocean: LOICZ
• Vulnerability of coastal systems & hazards to human
societies
• Implications of global change & land & sea use on
coastal development
• Anthropogenic influences
on the river catchment &
coastal zone interaction
• Fate & transformation of
materials in coastal &
shelf waters
• Towards coastal system
sustainability by managing
land-ocean interactions
44% of the world’s population live within
150 km of a coastline
Simulated Night Lights
2070
Image: H-J Schellnhuber
What is Global Change?
For example, changes in:
U.S. Bureau of the Census
FAO
NOAA
Mackenzie et al (2002)
Nitrogen fixation
Temperature
Biodiversity
Atmosphere composition
Population
N in the coastal zone
Forest cover
Fisheries exploitation
Richards (1991), WRI (1990)
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Fig7, Pg12
Source: Vitousek (1994) Ecology 75: 1861-1876.
Changes in N deposition
– Humans have already doubled the
flow of reactive nitrogen on the
continents, and some projections
suggest that this may increase by
roughly a further two thirds by 2050
Estimated Total Reactive
Nitrogen Deposition from
the Atmosphere
Accounts for 12% of the
reactive nitrogen entering
ecosystems, although it is
higher in some regions (e.g.,
33% in the United States)
Millennium Ecosystem Assessment 2005
Box5, Pg22
Source: P.Crutzen (1995) My life with O 3, NOx and other YZOxs. Les Prix Nobel
(The Nobel Prizes) 1995. Stockholm: Almqvist & Wiksell International. pp. 123-157).
Kulturnatten 2005
Aksel Walløe Hansen, NBI
Kulturnatten 2005
Aksel Walløe Hansen, NBI
Kulturnatten 2005
Aksel Walløe Hansen, NBI
Kulturnatten 2005
Aksel Walløe Hansen, NBI
The Stages of the Anthropocene
1. Pre-Anthropocene events:
Fire-stick farming, megafauna
extinctions, early forest clearing
2. Anthropocene Stage 1
(ca. 1800 - 1945). Internal
combusion engine, fossil fuel
energy, sci & tech
Stage 2
Stage 1
NOAA
3. Anthropocene Stage 2 (1945 - 2010 or 2020). The Great
Acceleration, new institutions and vast global networks
Anthropocene Stage 3 (2010 or 2020 - ?). Business-as-usual,
geo-engineering, or the Great Transition?
From: Steffen, Crutzen & McNeill, in prep, 2006
6
Integrated Scenarios
of the
Earth System
4
3
2
N.H. Temperature
(°C)
1
1
0.5
0
-0.5
1000 1200 1400 1600 1800 2000
0
IPCC Projections
2100 AD
Global Temperature (°C)
5
Kulturnatten 2005
Aksel Walløe Hansen, NBI
Claussen 2004
Red: Qaeros = 1.7 W m-2
Blue: Qaeros = 0 (no aerosol cooling effect)
From:
From: Andreae
Andreae et
et al.
al. 2005
2005
The Ruddiman Hypothesis
20,000
Years Ago
10,000
0
Years Ago
Present
GREENHOUSE EFFECT from human activities has warded off a glaciation that otherwise would have begun about
5,000 years ago. Early human agricultural activities produced enough greenhouse gases to offset most of the
natural cooling trend during pre-industrial times (yellow), warming the planet by an average of almost 0.8 degrees
Celsius. That early warming effect (a) rivals the 0.6 degrees Celsius (b) warming measured in the past century of
rapid industrialization (orange). Once most fossil fuels are depleted and the temperature rise caused by
greenhouse gasses peaks, the earth will cool toward the next glaciation - now thousands of years overdue.
Ruddiman (2005).
6
Aerosols, C feedbacks push climate higher;
massive impacts to humans
Loss of Greenland ice sheet
Large biodiversity loss;
coral reefs disappear
5
4
3
2
“Committed” Climate Change
N.H. Temperature
(°C)
1
Now
1
0.5
0
-0.5
1000 1200 1400 1600 1800 2000
0
IPCC Projections
2100 AD
Global Temperature (°C)
Earth System moves to a new state;
modern civilisation collapses
Ocean-Atmosphere
• Biogeochemical interactions
and feedbacks between ocean
and atmosphere
• Exchange processes at the
air-sea interface and the role
of transport and
transformations in
atmospheric and ocean
boundary layers
• Air-sea flux of CO2 and other
long-lived radiatively active
gases
www.solas-int.org
SeaWIFS, NASA/GFSC & ORBIMAGE
Anthropocene
Stage 2
(1945 - 2010/2020)
The changing ’human
enterprise’, from 1750
to 2000.
Note the start of the
’Great Acceleration’
around 1950, when
many activities began
or accelerated sharply.
From Steffen et al. 2004
Simulated Night Lights
2000
Image: H-J Schellnhuber