Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceans in a Warmer World ! Absorb/release heat/CO2, currents transport ! Increased evaporation from tropical ocean &quot; Warming/cooling, salinity effects Oceans in a Warmer World ! Increased evaporation from tropical ocean &quot; Water vapor is a major GHG # Warming effect ! Reduced reflection from reduced sea ice ! Plankton &quot; Export carbon in tissues, skeletons to deep sea &quot; Aerosol production &quot; Acidification &quot; Increased clouds # Reflect sunlight # Cooling effect &quot; Net effect unclear # Probably warming 2 ! Methane hydrates 1 Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceans in a Warmer World ! Decreased albedo (reflectivity) &quot; Reduced snow &amp; ice cover &quot; Reduced reflection of solar radiation # Warming effect positive feedback # Reverse of Snowball Earth formation 3 Positive Climate Feedback ! Positive ocean feedback with warming ! Evaporation 1. ! Temp + ! Water Vapor (GHG) ! Melting of snow and ice 2. ! Temp + ! Absorbed Radiation &quot; Reflected Radiation 4 Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Negative Climate Feedback ! Evaporation !&quot; Temp ! Clouds, Reflection CO2 Effects on Oceans ! More evaporation from low latitude ocean &quot; More rain &amp; snow at high latitudes &quot; Fresher poles &quot; Saltier subtropics ! Negative ocean feedback with warming &quot; Enough to offset positive feedback from: # Increased water vapor? # Increased absorption due to reduced snow &amp; ice? # Probably not 5 ! Acidification &quot; ! pH 8.15 to 8.05 &quot; Dissolves CaCO3 6 # Coral reefs # Plankton Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Ocean Biology Cooling Effects ! CaCO3 skeletons remove CO2 &quot; Sink to deep water &amp; sea floor &quot; Released again when carbonates weather Methane Hydrates ! Major source of Gas Hydrates &quot; Frozen water + methane gas # Stable under pressure ! Phytoplankton photosynthesis (CO2 uptake) &quot; Sinks to deep water &amp; sea floor # Biological Pump =&quot;Permanent&quot; removal? &quot; Could be liberated by warming of deep water # Probability of release unknown ! Phytoplankton aerosol production &quot; e.g. sulfate SO4, dimethyl sulfide DMS &quot; Blocks sun &amp; encourages cloud formation 7 8 &quot; Large potential warming effect # (20x CO2e) Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Evidence of Ocean Changes ! Increased global heat content of ocean over last 40 years &quot; Modeled (shaded region) vs. observed (dotted line) oceanic heat content, averaged from the ocean surface to 3000 meters &quot; Barnett et al. (2001) Science http://www.sciencemag.org/ cgi/content/full/292/5515/270 Evidence of Ocean Changes ! Increased evaporation &amp; surface salinity in tropical Atlantic (Ruth Curry et al., Woods Hole, 2003) www.whoi.edu/institutes/occi/currenttopics/abruptclimate_rcurry_pr_en1.html 9 10 Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Evidence of Ocean Changes ! Decreased deep water salinity in subpolar Atlantic &quot; Increased river input to Arctic Ocean (Curry) Evidence of Arctic Changes ! Departure of Arctic annual temperature from long-term average since 1900 &quot; Previous warming 1920-40 &quot; Current warming since ~1970 12 Air temp. data from land stations www.whoi.edu/institutes/occi/currenttopics/abruptclimate_rcurry_pr_en1.html 11 Arctic Climate Impact Assessment (U of AK): http://www.taiga.net/acia/ nding01.html Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Evidence of Arctic Changes ! Reduced depth &amp; extent of Arctic sea ice &quot; Measured during September &quot; nsidc.org/news/press/20041004_decline.html (National Snow and Ice Data Centre, UCBoulder) Evidence of Arctic Changes ! More widespread melting of Greenland glaciers &quot; &quot; Measured by LIDAR (airborne laser radar) svs.gsfc.nasa.gov/stories/greenland/ ! Red &amp; yellow = increased ice thickness ! Blue = decreased ice thickness ! Magenta = average ice edge (recession) ! Note decreased ice extent off eastern Greenland ! Reduced surface salinity around Greenland 14 www.whoi.edu/institutes/occi/images/DicksonSalinityMap.swf 13 Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Evidence of Arctic Changes ! <a href="/keyword/greenland-ice/" >greenland ice</a> melt is accelerating Thicker, Thinner in Greenland ! <a href="/keyword/greenland-ice/" >greenland ice</a> depth 2006 &quot; Thicker in uplands # Increased snowfall Konrad Steffen and Russell Huff, Cooperative Institute for Research in Environmental Sciences (CIRES), http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/ &quot; Offset by lowland thinning 16 15 # Warming http://www.solcomhouse.com/icecap.htm Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Latest Updates ! Cool trend 2007-09 &quot; Lowest arctic ice 2006 &quot; 2009 still 6th lowest -3.1% per decade The Great Climate Flip-Flop (Calvin)? ! Models suggest that present warming could cause abrupt cooling like Younger Dryas ! What could reduce bottom water formation? &quot; !General sea-surface warming = more buoyant &quot; Excess surface fresh water in subpolar N. Atlantic # !Moisture evaporated from the tropical oceans transported to high latitudes falls as rain &amp; snow # !Melting Greenland glaciers # !Melting Arctic sea ice nsidc.org/arcticseaicenews/2009/020309.html ! Greenland melt 12/07 &quot; 2007 area 10% below 2005 # 30% more since 1979 &quot; Air temp. +7 C since 1991 # www.geologytimes.com/Research/ Greenland_Melt_Accelerating.asp # climateprogress.org/2008/12/18/greenlandantarctica-ice-loss-sea-level-rise/ 17 18 &quot; Evidence of recent 30% decrease in NADW formation (Byrden et al. 2005, Nature) Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Ice Age History &amp; Humans ! <a href="/keyword/greenland-ice/" >greenland ice</a> record of last 250 KY, 2 ice ages &quot; H. erectus gave way to H. sapiens 250 125 KYA Future Fluctuations &amp; Humans ! Europe s present climate anomalously warm &quot; Europe 9 18 F warmer than areas at same latitude &quot; Sinking salt water draws warm water North # 30% heat bonus ! Present warm period began abruptly 15 KYA &quot; About when modern civilizations began ! Cooling period 4200 YA # Collapse of Mesopotamian civilization ! Ice melt reduces Albedo (re ection), adding to warming ! Failure of warm current would be felt worldwide &quot; Swamps produce less methane &quot; Deserts release more dust &quot; Stronger wind 20 ! The Little Ice Age 15th 18th century &quot; Europe cooled by about 1.5 2.0 C # Vikings abandoned Greenland 19 Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Future Fluctuations &amp; Humans ! Would begin as drought &amp; cooling in Europe &quot; Another Little Ice Age # Change (1 2 C) within a few years Definition of Acidification ! Index of acid (low pH) vs. alkaline (high pH) &quot; 0 6 = acid, 7 = neutral, 8 14 = alkaline &quot; Each is a power of 10 difference in acidity &quot; 10X greater changes (10 20 C) in a decade or two ! A population crash that would &quot;end civilization within a decade&quot; (Calvin) &quot; Europe with Canada s climate could feed only 28 million of its 650 million people # Border wars &amp; disruption of supply routes &quot; World War III (Pentagon study 2003)? 21 # www.gbn.com/consulting/article_details.php?id=53 22 www.phschool.com/atschool/science_activity_library/acids_and_bases.html Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Ocean Carbon Chemistry ! ~1/3 of fossil-fuel CO2 dissolves in ocean &quot; Fizz in soda is dissolved CO2 being released &quot; Forms Carbonic Acid Effects of Ocean Acidification ! CO2 attacks calcium carbonate shells &quot; Also makes it hard to form shell to begin with ! Vulnerable organisms: &quot; Coccolithophorids (phytoplankton) &quot; Pteropods, forams (zooplankton) &quot; Coral reefs ! Fate depends on relative balance with calcium &quot; 1. Early Earth, post- Snowball Earth # Large amounts of freshly eroded calcium in ocean # CO2 &amp; calcium combine to form limestone sediment &quot; 2. Modern ocean CO2 &amp; calcium in balance # Excess CO2 acid dissolves calcium carbonate 23 24 cics.umd.edu/~chrisb/ehux_www.html, www.pmel.noaa.gov/co2/OA/ Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Status of Ocean Acidification ! Ocean CO2 rising &amp; pH falling (acidifying) &quot; Data from Hawaii &quot; Some locations worse Status of Ocean Acidification ! Deep water high in CO2 &quot; Respiration &amp; decay, no photosynthesis ! Worldwide average 8.16 drops to 8.05 &quot; Decrease of 0.1 pH unit = 25% more acid &quot; 0.2 0.4 drop by 2100? 25 www.us-ocb.org/index.html ! Acidification potential greatest where deep water surfaces &quot; West coast upwelling &quot; Red = depth of calcium dissolution &quot; Surface off N. California 26 &quot; www.sciencedaily.com/releases/ 2009/02/090201124553.htm www.us-ocb.org/index.html Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Oceanography 102, Strickland/Nuwer Lecture 18 2009 University of Washington Status of Ocean Acidification ! Slowing growth of Great Barrier Reef &quot; 14% reduction in skeletal formation since 1990 # www.sciam.com/article.cfm?id=ocean-acidification-hits-great-barrier-reef Status of Ocean Acidification ! Monaco Declaration January 30, 2009 &quot; Since the industrial revolution, the acidity of ocean surface waters has increased by 30 percent...about 100 times faster than for previous acidification events experienced in many millions of years. &quot; by 2030, the Southern Ocean will start to become corrosive to the shells of some marine snails that swim in surface waters. &quot; immediate action ... to avoid widespread and severe damage to marine ecosystems from ocean acidification. www.ocean-acidification.net/ ! Experimental corrosion of calcium shells &quot; Pteropod (48 hrs) b = acid, c = normal seawater 27 www.pmel.noaa.gov/co2/OA/ 28