Climate Change, Global Warming & Ocean Biology Doug Capone May 2008
Disclaimer: I m a Microbial Ecologist not a Climate Dynamicist IPCC 4 th Assessment And I d rather have a bottle in front of me than a frontal lobotomy
Take Home Messages What is Climate? Its the average weather Climate is what you expect Weather is what you get! Human-induced climate change has been difficult (but not impossible) to discern There are many dimensions to current rapid climate change Is there an Ocean Biology solution??
What Causes Climate Change? Some change is natural On long term, temperature co-varies with greenhouse gases Addition of greenhouse gases by humans Carbon dioxide, methane, nitrous oxide, CFCs Fossil fuel and biomass burning, industrial activity, farming
Climate change is natural Secular versus cyclic change Various Timescales Daily/ seasonal Decadal Millennial (glacial-interglacial) interglacial) Milankovitch cycles Geological (epochs, eras, eons)
Rise in Oxygen over Earth History billions & billions of years Major Variations in CO 2 millions & millions of years Glacial- Interglacial CO 2 and CH 4 variation thousands & thousands of years
Time-scales of Human Concern Rapid climate change Multi-year to decadal + Natural Oscillations- different periods Pacific Decadal Oscillation (20-30y) NW salmon fishery North Atlantic Oscillation) El Nino/La Nina (ENSO) (6-10y) Anchovy fishery
El Nino/ Southern Oscillation Normal El Nino La Nina
The Anthropocene Mankind growing influence on the environment During the past three centuries: Human population has increased tenfold (expected to reach 10 billion in this century). The number of methane-producing cattle has risen to 3 billion About 30-50% of the planet s land surface is exploited by humans More than half of all accessible freshwater is used by mankind Fisheries remove between 25-35% of the primary production
Fossil-fuel burning and agriculture have caused substantial increases in the concentration of Greenhouse gases- carbon dioxide by 30% and methane by more than 100%-reaching their highest levels over the past 400,000 years The Earth will warm by 1.4-5.8 C during this century
Oceanic Connection Much of CO 2 injected into atmosphere is missing. Missing Carbon in Sea? Role of Oceanic Biota in control? Natural uptake- Primary production preservation of carbonates petroleum in sediments Ocean fertilization??
Annual Increase in Atmosphere = 3 2 60 100 5 Fossil Fuels Deforestation Global Carbon Cycle (billions of tons of carbon/year) Land Biota 61 102-104 Oceans (Biology and Physics) 38,000
Relatively steady increase for last century IPCC 4 th Assessment- 2007- There is a discernable
Potential Effects Changes in Ocean currents/ heat transfer Changes frequency of storms Changes size of deserts Ice cap melting Sea level rise (meters to 10s of meters) Shifts in oceanic production Direct & indirect fisheries impact (food, currents, fish disease) More frequent, larger plankton blooms noxious; oxygen depleting; toxic Expansion of human disease organism in sea
Complex Responses Upper ocean warming Increased stratification Decreased nutrients Increased anoxic zones Increased dissolved CO 2 concentrations Positive plant responses Negative animal responses Decreased ph (acidity) Corals & coccolithophores
The Carbon and Nitrogen cycles are closely linked The formation of new organic matter in the Ocean is largely limited by nitrogen availability Phytoplankton need nitrogen to grow (like your garden)
Ocean Iron Fertilization for C Sequestration In addition to CO 2, and N, phytoplankton Need other nutrients P, S, Fe Some areas of the ocean- iron is in shortest supply Iron fertilization zones
In situ Iron Fertilization experiments in the Southern Ocean
Take Home Messages What is Climate? Its the average weather Climate is what you expect Weather is what you get! Human-induced climate change has been difficult (but not impossible) to discern There are many dimensions to current rapid climate change Is there an Ocean Biology solution??