The Nuts and Bolts of Climate Change Steve Jennings Department of Geography and Environmental Studies Colorado Geographic Alliance

CLIMATE CHANGE Earth systems are dynamic with complex interactions between different locations in respect to flows of energy and material. Variability is inherent in these interactions. Variability happens on a variety of temporal and spatial scales.

CLIMATE CHANGE Weather vs. climate is an example of scale variability. Weather is the conditions at any given time. Climate is the long-term variability of weather variables (e.g., temperature, precipitation, wind speed and direction). Weather conditions are expected to fall within the variability defined by the climate.

CLIMATE CHANGE Systems can be either open or closed. An open system has both inputs and outputs of energy and material, while a closed system is one that has no inputs or outputs. Most Earth systems are open systems, although the Earth itself is essentially a closed system for material, but not energy. Longwave Energy (open system) Solar Energy Earth material (closed system) Sun Earth

CLIMATE CHANGE Rainfall (material-water) (energy-gravity) Hillslope (material-sediment) (energy-gravity) Stream flow (material-water and sediment) Evaporation (material-water) (energy-heat) The flows of energy and material in a system have a role in regulating the functions of that system. This is called feedback. There are two kinds of feedback, negative and positive.

CLIMATE CHANGE Negative feedback involves a change in one part of the system, either an increase or decrease, that leads to an opposite change in another part of the system. increase decrease decrease increase an increase in snow cover in an area leads to a decrease in temperature because of the reflection of incoming solar energy.

CLIMATE CHANGE Positive feedback involves a change in one part of the system, either an increase or decrease, that leads to the same change in another part of the system. increase increase decrease decrease a decrease in stream flow leads to a decrease in the transport of sediments in a river.

CLIMATE CHANGE Systems with steady inputs of energy and materials often reach a steady-state equilibrium. There are fluctuations, but they are centered around a stable average.

CLIMATE CHANGE If the average is changing over time this type of system can be said to be in dynamic equilibrium. Some systems may reach a threshold at which there is a dramatic change in the system.

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CLIMATE CHANGE 1966 photograph Argentiere glacier in the French Alps 1850 etching

CLIMATE CHANGE Variation in carbon dioxide, temperature and dust from the Vostok ice core for the past 450,000 years. http://en.wikipedia.org/wiki/Climate_system

CLIMATE CHANGE Variability in Earth systems have direct impacts on humans who are dependent on a variety of resources. Temperature Water supplies Biotic systems

CLIMATE CHANGE Impacts on humans from climate change. Note that these are all water related. http://www.water.ca.gov/climatechange/factsheet.cfm

CLIMATE CHANGE The Earth system’s source of energy is the sun. The sun releases electromagnetic energy at a relatively constant rate and proportion of wave lengths.

CLIMATE CHANGE Most of the energy emitted from the sun is visible light. Visible light is short wave radiation which is produced by because of the high temperature (15,000 oF) of the sun. This energy radiates out into space to reach the Earth which is in just the right location to receive energy which keeps the Earth from being too hot or cold.

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CLIMATE CHANGE The Earth intercepts solar energy. Some of the energy is reflected back to space in the form of shortwave energy and some is absorbed by the Earth. Since the Earth is much cooler (15 oF) than the sun the electromagnetic energy emitted by the Earth is longwave energy. Longwave energy heats the atmosphere.

CLIMATE CHANGE Several factors influence the amount of energy that is retained in the Earth system. Day length Sun angle Composition of the atmosphere Reflectivity of the Earth’s surface and atmosphere

CLIMATE CHANGE Characteristics of the Earth’s orbit around the sun

CLIMATE CHANGE Tilt of the axis related to the position of the Earth in the orbit

CLIMATE CHANGE Angles of the sun’s rays depending on latitude

CLIMATE CHANGE The area receiving solar energy at different latitudes

CLIMATE CHANGE Attenuation of solar energy through the atmosphere

CLIMATE CHANGE Albedo (reflectivity) Earth surfaces http://en.wikipedia.org/wiki/File:Albedo-e_hg.svg

CLIMATE CHANGE Composition of the Earth’s atmosphere

CLIMATE CHANGE Changes in CO2 over time http://www.epa.gov/climatechange/science/recentac_majorghg.html#fig1

CLIMATE CHANGE Temperature and CO2 changes over time

CLIMATE CHANGE The Earth’s energy budget

CLIMATE CHANGE A representation of the Earth’s climate system http://www.ipcc.ch/ipccreports/tar/wg1/pdf/TAR-01.PDF

CLIMATE CHANGE Impacts of climate change http://www.epa.gov/climatechange/effects/extreme.html

CLIMATE CHANGE Severe weather events may be more common and stronger Heavier rainfall causes flooding The amount of drought may be increasing Sea level is rising Arctic sea ice is melting Sea-surface temperatures are warming Ecosystems are changing There have been changes in where we can farm

CLIMATE CHANGE Temperature change has been observed. In general higher air temperatures are being observed in many locations around the Earth. Some locations may have lower temperatures because of increased cloud cover and precipitation. The term global warming is somewhat misleading because there is not a wholesale change in temperature.

CLIMATE CHANGE Precipitation change over the last century http://www.epa.gov/climatechange/science/recenttc_tempanom.html

CLIMATE CHANGE Precipitation change may be the direct result of changing temperature patterns. Some areas may see decreased precipitation, others will have increased precipitation. Precipitation is related to the amount of evaporation and the temperature of the atmosphere. There appears to be a rise in the number of extreme precipitation events.

CLIMATE CHANGE Precipitation change over the last century http://www.epa.gov/climatechange/science/recentpsc_precipanom.html

CLIMATE CHANGE Increases in natural disasters http://en.wikipedia.org/wiki/File:Trends_in_natural_disasters.jpg

CLIMATE CHANGE Sea level is rising and ocean temperatures are rising. The amount of ice on the Earth’s surface is decreasing and liquid water is entering the ocean. Higher ocean temperatures are causing the thermal expansion of oceans.

CLIMATE CHANGE Sea level changes http://upload.wikimedia.org/wikipedia/commons/6/69/NOAA_sea_level_trend_1993_2010.png

CLIMATE CHANGE Sea temperatures http://marine.rutgers.edu/cool/sat_data/show/?file=../../regions/eastcoast/sst/noaa/2010/img/100308.067.1756.n19.jpg

CLIMATE CHANGE Changes in sea level for the last 9000 years http://upload.wikimedia.org/wikipedia/commons/1/1e/Holocene_Sea_Level.png

CLIMATE CHANGE Recent changes in sea level http://en.wikipedia.org/wiki/File:Global_mean_sea_level.png

CLIMATE CHANGE Sea level changes at selected locations http://upload.wikimedia.org/wikipedia/commons/7/7f/U._S._Sea_Level_Trends_1900-2003.gif

CLIMATE CHANGE http://www.epa.gov/climatechange/effects/coastal/slrmaps_sealevelmap.html

CLIMATE CHANGE Arctic Sea ice is melting. Open water affects the energy budget of the Arctic. Open water is less reflective of solar energy and therefore temperatures would continue to rise and there would be more ice melting.

CLIMATE CHANGE Changes in Arctic sea ice http://nsidc.org/arcticseaicenews/ http://nsidc.org/data/seaice_index/images/daily_images/N_daily_extent_hires.png

CLIMATE CHANGE Ecosystem change is occurring in many ways. Plant and animal distributions are changing. Many species are migrating poleward as a result of warmer conditions. Ecosystems are impacted as a result of drought stress. Insect infestations are increasing because of stressed plants.

CLIMATE CHANGE Predicted changes in the distribution of slash pine http://www.nrs.fs.fed.us/atlas/tree/future_iv_111.html

CLIMATE CHANGE Phenology network http://www.windows.ucar.edu/citizen_science/budburst/index.php

CLIMATE CHANGE Coral reefs are dying at a fast rate. Zooxanthellae the algae that grow in a symbiotic relationship with coral and supplies as much as 98% of coral’s food is adversely impacted by warm of water and increasing sediments in the water. The result is that the coral is left unprotected by the zooxanthellae and can die.

CLIMATE CHANGE The process of coral bleaching http://www.abc.net.au/news/stories/2009/11/04/2732742.htm?site=northqld http://www.gbrmpa.gov.au/corp_site/key_issues/climate_change/climate_change_and_the_great_barrier_reef/what_is_coral_bleaching

CLIMATE CHANGE Climate change is a controversial topic. Just as with any complex system it is hard to isolate components of the system. Sampling methods may not be representative of the entire sub-system being measured. It is hard to predict impacts and outcomes. It is hard to separate emotions from facts. Short term variability is not representative of long term trends.