* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PRESENTATION NAME
Climate resilience wikipedia , lookup
ExxonMobil climate change controversy wikipedia , lookup
Climate change denial wikipedia , lookup
Economics of global warming wikipedia , lookup
Climate sensitivity wikipedia , lookup
Global warming hiatus wikipedia , lookup
Climate change adaptation wikipedia , lookup
Climate governance wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Politics of global warming wikipedia , lookup
Global warming wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
General circulation model wikipedia , lookup
Media coverage of global warming wikipedia , lookup
Climate engineering wikipedia , lookup
Climate change and agriculture wikipedia , lookup
Global Energy and Water Cycle Experiment wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
Climate change feedback wikipedia , lookup
Citizens' Climate Lobby wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Effects of global warming on human health wikipedia , lookup
Carbon Pollution Reduction Scheme wikipedia , lookup
Effects of global warming wikipedia , lookup
Climate change in Tuvalu wikipedia , lookup
Climate change in the United States wikipedia , lookup
Solar radiation management wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
Ocean acidification wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
Climate change, industry and society wikipedia , lookup
Physical impacts of climate change wikipedia , lookup
Climate change and poverty wikipedia , lookup
The Oceans and Climate Change: Modern Pressures and Lessons from Ancient Examples Jennifer Latimer Department of Earth and Environmental Systems Outline • Current Environmental Issues Impacting the World’s Ocean • Lessons from Marine Records about Ocean Responses to Climate Change • Geo-engineering the oceans… Why are the oceans important? • Provide food • Help regulate planetary temperatures • Support coastal economies (i.e. fisheries and tourism) • Responsible for ~50% of carbon fixation (and production of oxygen) on the planet Environmental Issues Along Coasts • At least 50% of the world’s population lives near the coast • Coastal areas already deal with • Pollution: sewage, agricultural chemicals, heavy metals, plastics, etc. • Storms • Rising sea levels • Loss of wetlands and marshes Plastic Trash Dead Zones http://earthobservatory.nasa.gov/ Increased Pressures Resulting from Climate Change • Rising sea levels – sovereign island nations have already been forced to consider evacuation due to saltwater intrusion, erosion, and flooding • Tuvalo – South Pacific • Kiribati – South Pacific • Maldives – Indian Ocean • Marshall Islands – South Pacific • http://flood.firetree.net/ Increased Pressures Resulting from Climate Change • Sea Level Rise due to: • thermal expansion of water • melting glaciers and ice sheets • Greenland – 7 m • West Antarctica – 5 m • East Antarctica – 55 m • Estimated over 600 million people live in areas that are <10m above sea level • 2/3 of the world’s cities with populations over 5 million are in these same areas Increased Pressures Resulting from Climate Change • Another consequence of ice sheets melting is a change in thermohaline circulation – which contributes to heat transport and weather patterns • Deepwater today forms at the high latitudes where water is cold and salty • If deepwater is not dense enough it will not sink and disrupt thermohaline circulation • Impact continental temperatures in northern Europe • Impact carbon fixation in the oceans (primary productivity) Increased Pressures Resulting from Climate Change • Oceans absorb ⅓ – ½ of anthropogenic CO2 emitted • Changes in ocean pH – the oceans are becoming more acidic • From ~8.2 to ~8.1 over 250 years • Geologic and model evidence suggests this is a larger change in pH than has occurred in the past 300 million years • The rate of change is much higher than due to geologic causes Increased Pressures Resulting from Climate Change • As more and more CO2 is pumped into the atmosphere, the oceans become less able to resist changes in pH • If the rate of change is not slowed, pH will drop by another 0.5 units this century changing carbonate chemistry significantly in the oceans. • 60% drop in available CaCO3 • Adversely affect primary productivity in the oceans (carbon fixation) • Impact most ocean ecosystems Cenozoic Climate Change Cretaceous • Greenhouse World • High CO2 • High sea levels ocean… PETM • Interval of rapid global warming 55.8 million years ago • Global temperatures rose over ~20 thousand years • The event lasted ~180 thousand years • Deep sea extinctions resulted • Localized anoxia in the oceans • Large scale changes in ocean circulation • Surface waters more acidic Pleistocene Climate Kump (2002) after Petit et al. (1999) • Temperatures and CO2 varied in a cyclic pattern Since the LGM… • Stadial (i.e. Younger Dryas, 8.2 kyr event) and interstadial events (Bolling-Allerod) • Younger Dryas – rapid return to glacial conditions (maybe as few as 10 years) while recovery lasted 40-50 years • Mideval warm period and Little Ice Age – not as severe as previous glaciations • Holocene climate has been relatively stable • Studies of abrupt climate change teach us that climate can change in decades What we have learned… • Oceans and marine processes during a Greenhouse World are fundamentally different • Transient climate events are much shorter than the time it takes for natural processes to recover • We have already exceeded the natural variability in the carbon cycle of the last million years • Abrupt climate change can be on human time scales Geoengineering the Oceans • When a major climate change catastrophe occurs or a series of catastrophes occurs…people will demand action… • One of the quickest responses could be ocean iron fertilization, but…will it work? • Scientific community says – NO…maybe? – “Ocean fertilization: Time to Move on” Nature, October 2009 • Currently UN restrictions on iron fertilization Geoengineering the Oceans Boyd et al. (2007) Geoengineering the Oceans Boyd et al. (2007) Adding soluble Fe to Fe-deficient waters always results in higher rates of primary productivity!!! Geoengineering the Oceans • Rationale… – Iron is the limiting nutrient in some regions – “natural” process – artificial iron fertilization mimics a dust storm • Iron fluxes in the ocean not controlled completely by dust • Lefevre and Watson (1999); Watson et al. (2000); Latimer and Filippelli (2002); Ridgewell and Watson (2002); Blain et al. (2007); Latimer and Filippelli (2007); Meskhidze et al. (2007); Anderson et al. (2010) Geoengineering the Oceans • Instead of buying and selling C credits, buy Fe and pay someone to “dump” it in the ocean, which theoretically = C sequestration Geoengineering the Oceans • October 2009 – dust storm in Australia dumped 3 million tons of dust (N & P) into Sydney Harbor and the Tasman Straits – Phytoplankton tripled – Boost fishing industry and feed people? – Slow climate change Geoengineering the Oceans • Original Fertilization Plan: Add iron to iron depleted areas to stimulate phytoplankton • Newer Fertilization Plan: Add nitrate and phosphate to stimulate phytoplankton • Instead of buying and selling C credits, buy fertilizer and pay someone to “dump” it in the ocean, which theoretically = C sequestration (but probably not…) Geoengineering the Oceans • Other consequences… – Algae associated with HABs along coasts also thrive in iron fertilized patches of open ocean (Trick et al. 2010; Silver et al., 2010; PNAS) – Pseudonitschia produce domoic acid, a potent neurotoxin • Responsible for marine mammal and bird deaths • In some cases become dominant species and produce more domoic acid Geoengineering the Oceans • Other consequences… – Extensive ocean anoxia Potential long-term outcomes for iron fertilization of the ocean are unknown, and could include newly productive fisheries and reduced atmospheric carbon dioxide (left) or a polluted ocean, unenhanced fisheries, and little effect on atmospheric carbon dioxide (right). Credit: Jack Cook, Woods Hole Oceanographic Institution