10.3 Global Climate Change

Warm-up Essential Question What main factors contribute to climate? What happens if one of these factors changes? Essential Question What are the causes and impacts of climate change?

Climate Change- Mean Annual Global Temperature 1880-2015

First… Climate change vs. global warming Global warming is average temperatures for the WHOLE PLANET, which is increasing Climate change is the change in regions because of that global change

Climate Change Terminology Greenhouse Gas Gas that absorbs infrared radiation Ex: Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and tropospheric ozone Positive Feedback Change in some condition triggers a response that intensifies the changed condition Infrared Radiation Radiation that has a wavelength that is longer than that of visible light, but shorter than that of radio waves Greenhouse Effect Increase of heat in a system where energy enters (often as light), is absorbed as heat, and released sometime later

Climate Change Evidence for Climate Change Last decade is the hottest ever recorded The three hottest years ever recorded were the last 2015, 2016, and 2017 Phenological spring in N. hemisphere now comes 6 days earlier (phenological is based on times of plants emerging) Warming is not due to natural causes Human produced greenhouse gases are most plausible explanation

Causes Greenhouse gas concentrations increasing 2017 concentrations 408 ppm 1,834 ppb 328ppb 516ppt 232ppt

Causes Increased concentration of CO2 (right) Burning fossil fuels in cars, industry, and homes Deforestation Burning of forests

Greenhouse Effect

Other Pollutants Cool the Atmosphere Atmospheric Aerosols tend to cool the atmosphere Both human and natural sources Tiny particles that remain in troposphere for weeks or months Contain many chemicals, but often contain sulfur (makes acid rain – remember Venus) Complicates models of climate change Allows for people to argue.

Climate Change- Mean Annual Global Temperature 1880-2015

Climate Models Climate affected by: winds, clouds, ocean currents, and albedo Used to explore past climate events Advanced models can project future warming events Models are only as good as the data and law used to program them They have limitations

Climate Models

Effects of Global Climate Change Ocean as CO2 sink - excess CO2 is starting to harm ocean life

Effects of Global Climate Change- Melting Ice and Rising Sea Levels Sea level rise caused in 2 ways Thermal Expansion Water expands as it warms Melting of land ice Retreat of glacier and thinning of ice at the poles Melting has positive feedback Increased melting decreases ice, which decreases albedo leading to further warming

Melting Ice and Rising Sea Levels

Migration of barrier islands There will always be islands off the shore of the East coast, but they are moving because sea level is rising

Case-In-Point Impacts in Fragile Areas Eskimo Inuit live traditional life dictated by freezing climate Climate change is altering their existence Wildlife are smaller or displaced Reduced snow cover and shorter river ice seasons Thawing of permafrost (right)

Effects of Global Climate Change- Changing Precipitation Patterns Some areas will get more water, some areas will have greater droughts Extreme weather events will increase in number and intensity Ex: Hurricanes will likely get stronger and more frequent

Effects of Global Climate Change- Effects on Organisms Zooplankton in parts of California Current have decreased by 80% since 1951 Effecting entire food chain Decline in krill around Antarctica Caused decrease in penguin populations Species have shifted their geographic range Migrating birds are returning to summer homes earlier Food is not available at this time

Effects on Organisms - Coral Reefs Coral reefs can be bleached (right) due to increase in water temperature Affects coral symbiotes and makes them more susceptible to diseases to which they would otherwise be immune

Effect on Organisms - Vegetation Beech Tree Range

Effects on Human Health Increased number of heat-related illnesses and deaths

Effects on Agriculture Difficult to anticipate Productivity will increase in some areas and decrease in others Rise in sea level will inundate flood plains and river valleys (lush farmland) Effect on pests is unknown Warmer temperatures will decrease soil moisture- requiring more irrigation Location (i.e. elevation and altitude) where certain crops can be grown may have to change Decrease in crop yields in warm climates

International Implications of Climate Change Developed vs. Developing countries Differing self-interests Differing ability to meet the challenges of climate change

Common Denial Techniques It was cold this winter! No such thing as global warming Remember some areas will get more extreme weather, that includes extreme cold at very specific times Its about averages not specific locations

Common Denial Techniques It’s from the sun, the solar activity is warming the planet Actually solar activity hasn’t changed drastically Our atmosphere protects us from most of that Activity doesn’t match temperature

Common Denial Techniques Climate computer models are uncertain Nope. They could accurately predict the climate from the last 100 years. There is a very small margin of error on those models

Common Denial Techniques Carbon dioxide is plant food so its good This only applies when it’s in balance

Common Denial Techniques Antarctic sea ice is expanding Only because it’s coming off the land Also, it does in the winter every year but it’s less than it should be

Common Denial Techniques Well some people have data that says it’s not actually getting any warmer and it doesn’t correlate with CO2 This data is hacked Displayed skewed on the graph Taken from ONLY one place

“There were rumors of unfathomable things, and because we could not fathom them we failed to believe them, until we had no choice it was too late.”