Transcript Thinning of the Arctic Ice Decline in Arctic Sea Ice Extent

OCEANS AND GLOBAL CHANGE
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PROFESSOR A.E. HILL
DIRECTOR
NATIONAL OCEANOGRAPHY CENTRE,
SOUTHAMPTON
UK
GLOBAL CHANGE
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OCEAN-ATMOSPHERE-ICE
BALANCE
What does it mean?
Ocean-atmosphere-ice system out of normal balance
Changes at an unprecedented rate (last 1 M yrs)
Why does it matter?
Global change impacts Europe
Local and regional impacts
Impacts on the Global economy
The oceans
are integral to understanding and predicting
changes in the global environment
LIVING ON A CHANGING EARTH:
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THE CHALLENGES FOR SCIENCE
What is going on now ?
fundamental understanding of basic earth system processes
• Continuous awareness of change
sustained observing
• What is going to happen next – especially locally ?
predictive capability
• Finding solutions
evidence based policy, regulation, technology solutions, innovations to grasp opportunities and minimise risks
OCEANS AND GLOBAL CHANGE -
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HOT TOPICS
• SEA LEVEL CHANGE
• OCEAN ACIDIFICATION
• ARCTIC ICE THINNING
MEAN SEA LEVEL CHANGES
Past 200+ years observed, next 100 years predicted
•Permanent Service for Mean Sea Level www.pol.ac.uk/psmsl
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global rise of approximately 10-20 cm during the past 100 years
(IPPC 3rd Assessment Report)
IPCC Third Assessment Report
Predicted 9-88 cm (central value 48 cm)
OCEANS AND GLOBAL CHANGE
EXTREME SEA LEVEL EVENTS THAT CAUSES FLOODS
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COASTAL AREAS AT RISK
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By 2100
The 1 in 100 year
flood level (shown
here in red) may
become a
1 in 10 year level
SEA LEVEL COMMITMENT – living with the consequences
Sea level will continue to rise even after CO2 emissions are reduced
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Third IPCC Assessment Report
EUROPEAN SEA LEVEL OBSERVING NETWORK (ESEAS)
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www.eseas.org
REDUCING UNCERTAINTIES: THE ABILITY TO PREDICT?
NORTHWEST EUROPE STORM SURGE SCENARIOS: Computed change in 50-year surge
Source: Proudman Oceangraphic Laboratory www.pol.ac.uk
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Storm Surges with ECHAM4 – T102
Range of values -20 to +40cm.
Storm Surges with HADCM2 climate
OCEAN ACIDIFICATION
Fossil Fuel CO2 is invading the Ocean
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ATLANTIC
PACIFIC
Source: Sabine et al (2004)
Science, 305:367-371
INDIAN
The Extra CO2 is Acidifying the Ocean
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Source:
Caldeira &
Wickett (2003)
Nature, 425:365
Particular Concern for Organisms with Chalk Shells or
Skeletons
•coral reefs
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coralline algae
coccolithophores
foraminifera
pteropods
Source:
Royal Society
report on
ocean
acidification
(2005)
Malformed coccoliths at high CO2
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Normal CO2
High CO2
Source: Riebesell et al (2000) Nature, 407:364-367
OCEAN ACIDIFICATION
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What We Know
1. Ocean acidification is already happening
2. If emissions continue oceans will inevitably become ever
more acidic
3. Coral skeletons and chalk shells will be affected
OCEAN ACIDIFICATION
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What We Need to Find Out
1. How will the organisms be affected by thinner shells and
weaker skeletons?
2. What other effects will follow from lowered pH?
3. What will be the knock-on effects on marine ecosystems and
the ocean carbon cycle?
“Thus chemical effects of CO2 on the marine environment may be as
great a cause for concern as the radiative effects of CO2 on Earth’s
climate.” [Caldeira & Wickett (2005) J. Geophys. Res. 110, C09S04]
FISH AND CHIPS or JELLYFISH AND CHIPS ?
THE ARCTIC OCEAN:
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SHRINKING SEA ICE COVER
Bad news for Polar Bears ... but also...
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RAPID CLIMATE CHANGE:
The freshening of Arctic and sub-Polar seas
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As the sea ice melts the
Arctic ocean is
freshening. This will
lessen the production of
dense salty deep water
and could result in
changes to the ocean
circulation
NORTHWEST EUROPE IS WARMER THAN IT SHOULD BE
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FRESHENING OF HIGH LATITUDE WATERS COULD SLOW SINKING
AND RELEASE OF HEAT TO THE ATMOSPHERE
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The temperature
rise/fall relative to preindustrial for the first
decade after a
collapse in 2050
(Hadley Centre)
With a simple model
the probability of
collapse by 2100 is
about 30%
RAPID CLIMATE CHANGE
SCIENCE FOR DEVELOPING A LONG TERM OBSERVING SYSTEM
FOR ADVANCE WARNING
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WHO WILL EUROPE‘S MAJOR TRADING PARTNER BE IN 2025?
Will Europe increasingly face north?
Economic, Social and Environmental implications?
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The North West Passage in September 2005
MARINE SCIENCE
THE GLOBAL ENVIRONMENTAL CHALLENGES FACING EUROPE:
SOLUTIONS THROUGH PREDICTION - NOW IS THE TIME TO INVEST
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Big questions
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Massive implications (environmental, social, economic)
Fundamental marine science at the heart of these
Addressing
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What is going on now ?
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How can we be more continually aware of changes ?
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What is going to happen next?
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What solutions can help us live with a changing world?
Needing
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A healthy marine science base (people and the major infrastructure to support marine science)
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Robust approach and funding mechanisms for sustained marine observing
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Well focussed coordinated marine science programmes
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Strong knowledge transfer - marine science into policy and business opportunity
CONCLUSIONS
WE LIVE ON A PLANET NOW OUTSIDE ITS NATURAL RANGE AND CHANGING AT AN
UNPRECEDENTED RATE
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• The Oceans are integral to understanding global
change
• The consequences of global change for Europe
present both risks and opportunities
• Key to preparation is better sustained observation
and prediction of marine systems
• Coordinated research to inform policies at European
level and to give European businesses the
competitive edge is vital
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OCEANS AND GLOBAL CHANGE
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