Why cant we predict climate?We don’t understand non linear feedbacksNonlinear feedback: input does not equal outputShut off of thermohaline circulation possibly make Europe so cold all the crops would fail.Humans have a huge impact on climate, and we cant predict human activityModel TypesOne dimensional: temp change with respect to altitude, but ONLY in one location (ex: LA)Two d: account for different latitudes and altitudes3d: Earth divided into boxes. Earth latitude, altitude, and longitudeLand and water surfaces, and how processes differ with eachGCMs: General circulation model^^^These all tend to only account for water OR land, not bothESMs: Earth system modelCompares systems over water and landSome move through space, not timeRun until equilibrium is reached, but does not tell us how long it takes or how we get thereMore sophisticated models are time dependentHUGE amounts of commuting timeModel Resolution: everything in the box is equal, so the more, smaller boxes available, the more accurate it isSometimes, boxes extend across half of Florida and into the oceanDoes not account for the difference between cities and agricultureDO NOT WORRY ABOUT SUBGRID PARAMETERIZATIONValidating modelsBased on fundamental, very well understood scientific principlesChange radiative forcing and put it into the modelSuccessful reproduction of past and present climate (orbital forcing)Some aspects verified by natural experimentsMt. Pinatubo eruption in 1991 released a ton of ash/gasScientists tried to see what would happen if they put the ash in the atmosphere in their modelNature favored their modelDoubling of CO2 from pre-industrial rev measuresUsed to be 280, now 390Double current CO2 in ppm to view climate change in the future560 ppm3.5 deg C is the predicted model, we have 2.5 deg to go, inc by .8 since pre-industrial rev levelsCannot just focus on CO2 for global warming, bc CH4 and other greenhouse gases are also causing itConsequences of global climate changeRising sea levelsRate: 20k years ago, ocean was 400ft lowerBegan rising about 1cm per year, by 20th century it was a few mm/year, now its 3.5 cm/yearWays sea levels rise: Glaciers/permafrost, deposition of sediment by rivers, human alteration of hydrologic cycle (deplete ground water reserves  oceans as runoff)Could lose ice sheets bc water getting in their acts as a lubricant, meaning sea levels could rise by 10ft very quickly (without even melting)Less albedo bc less ice coverIncreased droughtsMore intense natural disasters bc warmer air can hold more water, but will not be equally distributed across the globeChange in agriculture and speciesDecrease in biodiversitySpecies migrating  Human health problem (mosquitos)6 km/decade northFasted warming we’ve seen since the next ice ageWe’ll lose species (trees) bc they do not move fast enoughPushing them further up  smaller area to live in  dec. number of speciesExtinction: 15-30% of all speciesFlowering, mating, nest building much soonerRegional areas accustomed to the diseases they have, so moving these diseases will kill peopleOcean acidificationOcean circulationMitigation: policy to reduce, trying to stop whats going on rather than just dealing with itAdaptation: Deal with whats happeningClimate and California 05/02/2013Why cant we predict climate? -We don’t understand non linear feedbacks oNonlinear feedback: input does not equal outputShut off of thermohaline circulation possibly make Europe so cold all the crops would fail. -Humans have a huge impact on climate, and we cant predict humanactivityModel Types-One dimensional: temp change with respect to altitude, but ONLY in one location (ex: LA)-Two d: account for different latitudes and altitudes -3d: Earth divided into boxes. Earth latitude, altitude, and longitudeoLand and water surfaces, and how processes differ with each-GCMs: General circulation model -^^^These all tend to only account for water OR land, not both-ESMs: Earth system modeloCompares systems over water and land -Some move through space, not timeoRun until equilibrium is reached, but does not tell us how long it takes or how we get there oMore sophisticated models are time dependent oHUGE amounts of commuting time Model Resolution: everything in the box is equal, so the more, smaller boxes available, the more accurate it is-Sometimes, boxes extend across half of Florida and into the ocean -Does not account for the difference between cities and agriculture-DO NOT WORRY ABOUT SUBGRID PARAMETERIZATION Validating models -Based on fundamental, very well understood scientific principles-Change radiative forcing and put it into the model-Successful reproduction of past and present climate (orbital forcing)-Some aspects verified by natural experiments oMt. Pinatubo eruption in 1991 released a ton of ash/gasScientists tried to see what would happen if they put theash in the atmosphere in their model Nature favored their model Doubling of CO2 from pre-industrial rev measures -Used to be 280, now 390-Double current CO2 in ppm to view climate change in the future o560 ppm3.5 deg C is the predicted model, we have 2.5 deg to go, inc by .8 since pre-industrial rev levels Cannot just focus on CO2 for global warming, bc CH4 and other greenhouse gases are also causing itConsequences of global climate change -Rising sea levelsoRate: 20k years ago, ocean was 400ft lower oBegan rising about 1cm per year, by 20th century it was a few mm/year, now its 3.5 cm/yearoWays sea levels rise: Glaciers/permafrost, deposition of sediment by rivers, human alteration of hydrologic cycle (deplete ground water reserves  oceans as runoff) oCould lose ice sheets bc water getting in their acts as a lubricant, meaning sea levels could rise by 10ft very quickly (without even melting)-Less albedo bc less ice cover -Increased droughts-More intense natural disasters bc warmer air can hold more water, but will not be equally distributed across the globe -Change in agriculture and species oDecrease in biodiversityoSpecies migrating  Human health problem (mosquitos)6 km/decade north Fasted warming we’ve seen since the next ice age We’ll lose species (trees) bc they do not move fast enoughPushing them further up  smaller area to live in  dec.number of species Extinction: 15-30% of all species Flowering, mating, nest building much sooner Regional areas accustomed to the