INVESTIGATING CLIMATE CHANGE USING OBSERVED TEMPERATURE DATA June 2011

The Intergovernmental Panel on Climate Change (IPCC) has concluded that the Earth’s average surface temperature has increased around one degree Fahrenheit in the last century. Fast growing warming trenth since the 70s Above: The National Climate Data Center (NCDC) comparison between the average global surface temperature (*C) to the 100-year average temperature for 1901-2000.

WHY DOES THIS MATTER? Long-term global climate change will cause problems such as: The melting of polar ice Droughts Changed precipitation patterns More severe weather All of these problems will have harsh effects on all ecosystems and the organisms living in them. For example, the melting of polar ice caps threatens that the global sea level will rise and also causes the ocean to be less salty, which affects fish and other marine organisms.

OUR CASE STUDY! In this case study, we will compare weather data from stations in Key West, Florida and Barrow, Alaska. We will look at how surface temperatures change in different locations throughout a year, between years and during a span of multiple years. We will look for the general trend of the change in surface temperature in both a cold climate and a warm climate. QUESTION: How have surface temperatures in Barrow, Alaska changed over time and how does this compare to climate change in other regions? What do these changes mean? KEY WEST, FLORIDA BARROW, ALASKA

What is GSOD and GSN? The two types of data we will be using to gather information are from the Global Summary of the Day (GSOD) and the Global Surface Network (GSN) Both can be accessed from the National Climate Data Center (NCDC)’s Geodata Portal This portal provides a vast range of free data sets collected from weather stations all around the world! NCDC = division of National Oceanic and Atmospheric Administration (NOAA)

Download weather data for Barrow, Alaska and Key West, Florida from NCDC Geodata Portal. To download data: Web Interface Search  DataSet/Product  Surface Data, Global Summary of the Day  Access Data/Products  Select country  Select State  Select Station ID/Station Name  Choose date range Download For this case study we will look at data from Barrow/W. POST – W R. and Key West Intl Arpt and Key West/Int (both cover same area in different years) Repeat steps for Surface Data, Monthly Global (over 900 worldwide sites) Review inventory data and enter email. When order is complete, you may download all the data files. We download both because with GSN we are able to see a broader range of data. GSOD is more specific, while GSN is the monthly average over a long period of time.

Barrow, Alaska Daily Temperatures Temperature (*F) Day of the Year

Barrow, Alaska Daily Temperatures Tempt (*F) The graph is bell shaped; it repeats its pattern every year; temperature extremes are greater when the sun does rise; this makes sense. Day of the Year (DOY)

Barrow, Alaska Daily Temperatures *F DOY

So What Do We See?? The average temperature of Barrow in 1946 is 9.86 *F while the average temperature of 2008 is 13.7 *F The mean temperatures of Barrow, Alaska in 2008 are generally higher than the mean temperatures of 1946 It is difficult to calculate the average yearly temperature of Barrow using the GSOD data because there is simply too much data. For this reason, in order to make it easier to search for a trend in the change in temperature, we will use GSN Data. This reports the average monthly temperature in a station over a period of time, making it easier for us to plot it.

Barrow, Alaska Monthly Temperatures *F the Global Surface Network (GSN) data. It is monthly average temperature data. Is is important to note that it is reported in degrees C rather than Fahrenheit as the GSOD data is. So for comparisons between stations, we will convert the GSN data to degrees F. It is faster to create annual average temperature with the GSN data – it is only 12 numbers, and we can use the month column to help us sort out the averages we want to graph. Month

Barrow, Alaska Monthly vs. Daily Temperatures *F Month Follows similar pattern, bottom is more condensed Temperature (*F) Day of the Year

Best fit line equation: y = 0.060x – 110 Above: the mean temperature for the month in Barrow, Alaska from 1948 to 2004. Best fit line equation: y = 0.060x – 110 The equation has a positive slope, indicating that the average monthly temperatures for Barrow are generally increasing. To determine how much temperature has risen; rise per year * number of years = 57 * .06 = 3.42* average increase in temperature (Fahrenheit).

Barrow, AK vs. Key West, FL (1948) Degrees F DOY Both stations are at sea level and also near the ocean Key West is nearer to the equator and therefore does not have freezing temperatures It is also surrounded by the ocean, which moderates warm temperatures, causing the difference in the shapes of the two plots

Average Annual Temperatures Key West, FL vs. Barrow, AK (1948-2002) TEMPERATURE ( *F) The equation for Barrow is slightly different than before because it starts in 1949 instead of 1948 and ends in 2002 instead of 2004. YEAR

OBSERVATIONS!! 0.0185 * 54 years = .999 *F rise in temperature for Key West, FL This is around the average rise in the last century globally Barrow, AK has warmed 3.5 *F from 1949 to 2002 Colder climates appear to warm at a faster rate than warmer ones Multiply the slope by the years to find increase

FURTHER STUDY To go beyond the case study, one may look at the temperature data for a more moderate area and compare it to that from the two we have already looked at For example: Temperature data from Syracuse, New York Syracuse has even less of a trend in temperature changes than Key West and also has a more pronounced curve indicating a wider range of temperatures during the year The equation of the trend line is y = 0.005x + 47.90. Average temperature in Syracuse, NY has increase 0.005 * 56 = 0.28 *F Average Annual Temperature Syracuse, NY (1946-2002) *F DOY Year number

CONCLUSIONS Since 1948, the average temperature in Barrow, Alaska has increased 3.42 degrees Fahrenheit while the average temperature in Key West, Florida has increased around one degree Fahrenheit Climate change in colder areas is occurring at a more rapid pace than in warmer ones Evidence shows that this climate change is caused my humans, therefore it is necessary to stop global climate change from progressing even further. Though climate change is generally characterized by rising temperatures, humans impact how big the change will be If places such as Barrow, AK will continue to warm at this rapid pace, there will be many negative consequences: Organisms living in these habitats will no longer be able to thrive there. They may soon face threat of extinction The melting of polar ice will cause the sea level to rise Melting glaciers will decrease the salinity of the water, setting off the balance of the ecosystems that lie below the surface Polar Ice is a sound source of water; without it there will be less freshwater available This means that humans should take steps to reduce the impacts of accelerated global climate change! In the study, Dr Barnett’s team examined more than seven million observations of temperature, salinity and other variables in the world’s oceans, collected by the US National Oceanic and Atmospheric Administration, and compared the patterns with those that are predicted by computer models of various potential causes of climate change. Population growth, emissions from cars (co2) and power plants

REFERENCES http://epa.gov/climatechange/index.html http://www.geology.wisc.edu/courses/g115/2ndCredit/Projects04/GlaciersWarming/christense/page1.html http://www.metrowestdailynews.com/news/x1685420566/Evidence-for-climate-change-caused-by-man-mounts http://www.timesonline.co.uk/tol/news/world/article516033.ece