Science Seminar

Unit 2

Kaplan University

The type of measurements that indicate climate change is occurring is the National Climatic Data Center; it contains the instrumental and paleoclimate records that will precisely define the nature climatic fluctuations. Other resources are ships, buoys, weather balloons, weather stations and many climate proxy records like tree rings and ice cores. The National Oceanographic Data Center receives the ocean data that can reveal the way heat is distributed and redistributed over our planet. Climate information goes on for hundreds and thousands of years, the paleoclimatology data helps provide longer term perspectives. Over the years reduced diurmal temperature range (DTR: the difference between daily high or maximum and daily low or minimum temperatures) over 70% of the global land mass since the middle of the 2oth century. The years between 1979-2005, the DTR shows no trend. There are many factors’ that contribute to the change in DTR, on a regional and local basis, which include changes in cloud cover, atmospherics water vapors, land use and urban effects. The challenges they face is trying to figure out if human activities are leading to an enhancement of the greenhouse effect by emission of greenhouse gases through fossil fuel combustion and deforestation. Concentration levels of carbon dioxide have risen since 2000. Our atmosphere exceeds the natural range over the last 650,000 years. The greenhouse effect is expected to cause a cooling in higher parts of the atmosphere because of increased effect in lower atmosphere holds more heat and this is causing less to reach the upper atmosphere. Since 1979 cooling of the lower stratosphere is shown by both Satellite Microwave Sounding Unit radiosonde data, but due to uncorrected errors in the radiosonde data it is showing much larger. Data sets are becoming more widely available and this is allowing research into changes in temperature and precipitation on global and regional scales. Paleoclimate data are found in sources like tree rings, ice cores, coral and lake sediments. It is not a comprehensive network of paleoclimate data as there is with instrumental coverage, so it makes it hard to obtain global climate reconstruction. With incomplete evidence they can only predict what will happen, for now it will be unprecedented in comparison with the best available records from the last several thousand years. Technology has come a long way, they are using a computer based mathematical models which can simulate, in three dimensions. These models are constantly improving based on our understanding and the increase in computer power. I have often wondered about what is causing all these changes in the weather that we are having from all the floods, earthquakes, tornadoes and when they had the Tsunami. Is it due to ocean changes or atmosphere changes?

References:
Global Warming Frequently Asked Questions retrieved on November 20, 2012 from:
http://www.ncdc.noaa.gov/cmb-faq/globalwarming.html