Past And Future Climate Changes

1. Past And Future Climate Changes Climatology is the study of climate. By Corryn Andrianus, Linda Morales, Andrea Busato, and Rachael Weyhe

2. How Do We Learn About Past Climates? • Use climate proxies – physical or biological clues • Ice cores- Gases and particles trapped in snowfall can be analyzed by examining ice layers. These substances represent atmospheric conditions at the time the snow fell, therefore telling us the temperatures and climate of area where the ice sheets are located • Tree rings- Varies in size depending on the temperature and precipitation conditions at the time of growth. Narrow rings are from cool, dry years, wider rings represent warm, wet years. • Sediments & sedimentary rocks- Certain plankton species that lived there are very dependent on the temperature. Once they die, they sink to the bottom of the lake. One type of species tells the temperature of the lake in that year Facts On File

3. What Have We Learned About What The Climate Was Like In The Past Compared to Now? • Global sea level rose about 17 centimeters (6.7 inches) in the last century • Levels of Carbon Dioxide are higher today than at anytime in past 650,000 years. • Global surface air temperatures rose three-quarters of a degree Celsius (almost one and a half degrees Fahrenheit) in the last century, • The Greenland and Antarctic ice sheets have shrunk in both area and mass. http://www.aboutmyplanet.com/files/2009/03/climate-change_1.jpg

4. What Have We Learned About What The Climate Was Like In The Past? Continued… • Mountain glaciers and snow cover have declined on average in both hemispheres, and may disappear altogether in certain regions of our planet, such as the Himalayas, by 2030. • Many species of plants and animals are already responding to global warming, moving to higher elevations or closer to the poles. • Precipitation and evaporation patterns over the oceans have changed, as evidenced by increased ocean salinity near the equator and decreased salinity at higher latitudes. http://geology.com/news/images/climate-change-animation.jpg

5. Determine Climate Change • Numerous long-term changes in the climate have been observed, including extreme weather such as droughts, heavy precipitation, heat waves and the intensity of tropical cyclones. • Warmer temperatures mean greater evaporation, and a warmer atmosphere is able to hold more moisture -- hence there is more water aloft that can fall as precipitation. Similarly, dry regions are apt to lose still more moisture if the weather is hotter; this exacerbates droughts and desertification. • The frequency of heavy precipitation events has increased over most land areas. Significantly increased precipitation has been observed in eastern parts of North and South America, northern Europe and northern and central Asia. • http://dsc.discovery.com/videos/earth-signs-of-climate-change-in-alaska.html Facts On File

6. What Are Examples of Places Scientists Find Information On Climate Change? • Long cores of ice obtained from Greenland and Antarctica are also widely used to measure past climate conditions, with this record extending back for about 650,000 years. • Drying has also been observed over large regions, i.e. the Sahel, the Mediterranean, southern Africa and parts of southern Asia. • In Africa's large catchment basins of Niger, Lake Chad, and Senegal, total available water has decreased by 40 to 60 percent, and desertification has been worsened by lower average annual rainfall, runoff, and soil moisture, especially in southern, northern, and western Africa. Facts On File

7. How Do We Predict Future Climates? • By reconstructing the past behavior of Arctic climate and ocean circulation • late 1800s: meteorologists have been measuring weather characteristics: temperature, precipitation, and wind speed • They find the weather’s direction from land-based stations from weather balloons • 1960: meteorologists began to use satellites to gather weather data. http://cache.gizmodo.com/assets/resources/2008/05/climate-change-google-earth.jpg

8. What Do Scientists Predict Will Happen To The Climate In the Future? • Scientists have high confidence that global temperatures will continue to rise for decades to come, largely due to greenhouse gasses produced by human activities. • According to the IPCC (Intergovernmental Panel of Climate Change), the extent of climate change effects on individual regions will vary over time and with the ability of different social and environmental systems to mitigate or adapt to change. • Contraction of snow cover areas, increased thaw in permafrost regions, decrease in sea ice extent • Increased frequency of hot extremes, heat waves and heavy precipitation • Increase in tropical cyclone intensity • Precipitation increases in high latitudes • Precipitation decreases in subtropical land regions • Decreased water resources in many semi-arid areas, including western U.S. and Mediterranean basin Facts On File

9. What Is The Intergovernmental Panel On Climate Change? • Also known as the World Climate Research Programme • First, this group started with 300 climatologists and upgraded to over 1,500 atmospheric scientists • They study and observe the changes in climate and weather http://www.matternetwork.com/images/Matter/climate_change.jpg

10. What Is Their Role In Understanding Climate? • suggested that global warming might have anthropogenic causes • led to the U.N.'s Rio Earth Summit in 1992 where 154 parties signed the U.N. Framework Convention on Climate Change • A 1995 report, this time representing a consensus of more than 1,500 IPCC atmospheric scientists, confirmed that the balance of evidence suggested "a discernible human influence on the climate system." • The scientists projected that over the next 100 years a temperature rise of 2 to 6.5 degrees http://cache.gizmodo.com/assets/resources/2008/05/climate-change-google-earth.jpg

11. How Do Humans Induce Climate Change? • Greenhouse gases- into the atmosphere (cars, factories, etc.) and chlorofluorocarbons (aerosol spray) • Land use changes- the conversation of forests to farms change the evapotranspiration level that alters the balance of heat and water • Global dimming- particles from burning fossil fuels pollute clouds and those clouds reflect light and cause decrease in temperature • Sea level rise-melting glaciers, sea leveling rising after use of fossil fuels and chlorofluorocarbons http://www.cosmosmagazine.com/files/imagecache/news/files/news/20090115_climate_change_aus.jpg

12. Suggested Websites: • http://www.epa.qld.gov.au • http://earthguide.ucsd.edu • http://www.ucar.edu/news/features Citations: • Facts On File: Science Online • Climate.nasa.gov • http://topics.treehugger.com/ http://www.dfg.ca.gov/climatechange/images/ClimateChange.jpg