Uncertainty in Climate Change

Climate change is typically defined as significant change in the measures that determine climate such as temperature, wind  or precipitation  over an extended period of time.  Factors that affect climate change include natural as well as human activity. One factor contributing to climate change is the increase of greenhouse gases in the atmosphere. While greenhouse gases help keep a moderating effect on the Earth’s temperature, the equilibrium of this system is changing with the rapid increase of greenhouse gases in the atmosphere caused by human activity. These human-driven activities include burning of fossil fuels, deforestation and urban and agricultural development. As the temperature in the atmosphere changes, climate changes occur. Climate change affects regions, ecosystems in those regions and even economies. According to the EPA Climate Change website, greenhouse gases are being monitored using a greenhouse gas inventory  which measures emitted or absorbed gases over a period of time. The EPA in the US tracks these absorptions and emissions as do many other countries, the data which helps formulate a global inventory. The use of these inventories help predict future emissions and absorptions. Trends, strategies and government policies are then formulated with the data collected.

There are several forcings and feedbacks that have raised questions and uncertainty about global warming. According to the  NASA GCC website, there are two forcings that scientists are looking at and developing future models for. One of the questions is about solar irradiance. There is no empirical data before the 1970’s so making conclusions based upon only forty years of evidence is difficult. Aerosols also raise some questions regarding their effects on  global warming. Aerosols are made of a variety of particles in both composition and size. Some of the lighter, brighter particles reradiate light back into the atmosphere while darker particles absorb the radiation thereby increasing temperature. Tracking of aerosols in the atmosphere has only been quantified in the last decade and the measurements make no distinction between the types of particles. According to the Earth Observatory website, some models have predicted that aerosol cooling can counteract global warming but the distribution of the particles is  not evenly distributed over the Earth.

Several feedbacks also raise some uncertainty because of insufficient data or knowledge. Cloud physics is not completely understood and difficult to model. Clouds cool the earth by providing shade and by reflecting light. They can suppress precipitation but could also form higher and taller clouds initiating more storms. According to the Earth Observatory website, clouds are a very large uncertainty in climate modeling and predictions. Carbon cycles involve both natural and human-made processes. Natural processes remove carbon emissions with oceans being the main repository. Ocean circulations especially in the Atlantic could potentially cool Europe and advance ice sheets. Data again is only represented since the 1990s.

Other models include those for precipitation. Some models predict a decrease in precipitation in the southwest US while other models ( JPL for example) show an increase in precipitation. NASA has also studied permafrost melt. As permafrost melts, it runs off into the oceans, increasing the amount of fresh water. Fresh water is less dense than salt water and floats on top. An increase of fresh water near the poles can change ocean currents which also affect atmospheric temperatures. Accuracy and uncertainty in climate models occurs due to insufficient or lack of long-term data as well as regional differences. Also contributing to the uncertainties is the incomplete climate knowledge as well as the natural variability of many factors contributing to climate change. . It is also difficult to predict exactly how much pollution humans will add to the atmosphere in years to come. (windows2universe.org). As we continue to explore and develop more climate models, these unknown factors will become more apparent. The data collected over a longer period of time will allow for more accurate predictions and mathematical relationships to be established. While time will indicate the extent of global climate change, it will also allow scientists to more accurately measure and use the data collected to predict more realistic scenarios.

Reviewing the 2007 IPCC report and the six emission scenarios proposed in the report, I can see many similarities regarding the evidence occurring today and possible future effects. With the burning of fossil fuels, our current global temperature is rising. With the  burning of fossil fuels without continued regulation (as seen in scenario A1F1), we will continue to see the global temperature rise. Human population is still increasing exponentially and more people on the planet will bring about more demand for resources. Some of the scenarios presented in the 2007 report reflect slow, isolated economies which can only hamper the progress that is being made in our time (A2). We are seeing some of the predictions for the next 100 years already occurring. We are seeing more flooding in low lying coastal and delta regions. Extinction rates are increasing due to climate change and the inability of some species to adapt to the changes. Migration patterns, flowering patterns and natural geologic events are changing due to changing weather patterns. We are seeing more severe weather events which in the report has predicted to only worsen. While many uncertainties are difficult to measure and collect data from, we can see effects already.  I think the biggest unknown factor in determining how the future scenarios will play out is human society itself. Will governments realize that policy changes and regulations need to establish to help combat the effects resulting by the  rise in global temperature  or will some governments resist change due to economic or political pressures? Will enough nations be able to sustain the demands on their economies that will occur with decreased crop production, increased disease and malnutrition? The IPCC have included some of these factors in their scenarios. While informing the public is crucial in addressing the problems we are facing now, it is paramount that we educate our young people. They are ultimately going to inherit the problems we are causing now and they will be the ones to hopefully find the solutions. The more  we address the unknowns and immeasurable factors in our lifetime, the uncertain factors that need to be investigated and studied, the easier the task will be for the future generations to implement more permanent solutions.

Lots of Ideas and so little time

When we address climate forcings and global warmings, we often look at it from a global perspective. With primary factors such as increasing GHG and man’s continued heavy use of fossil fuels, it is coming to light that more research is showing how local or regional climate changes are occurring at a faster rate than anticipated. We have been seeing the effects of greenhouse gases in the Southwest. The warming has been gradual and subtle but has had a profound effect on the region. Increased temperatures have reduced snowpack in the Rockies and caused earlier springs. The decrease in appreciable snow melt affects the water levels of the Colorado River on which we depend for our water needs. Add to that the winter storm track has been gradually sliding northward and we have less winter storms to supplement the snow pack. While this region has seen its share of droughts over the past 1000 years, determined by tree ring studies, we are finding that this drought that began in the 1990s is lasting longer than any natural drought previously seen. This can perhaps be attributed to human-induced GHGs.
As far as resources I use for teaching GCC, having almost all AP Biology classes, I am under the same time constraints as other AP teachers. Many topics get a once-over with the basic terminology covered and some local feedbacks examined. My sources have been primarily video clips or time lapse photography of ice sheets or mountain glaciers retreating. I have used the NASA satellite imagery to support the information  and rely primarily on the Keeling curve and hockey stick chart to illustrate the rise in GHG and global surface temperatures. We have had several interesting Socratic seminars based on the topic. I wish I had more time to spend on the topic and need to examine a way of integrating it into more of my course curriculum.
After reading several resources provided in the course, I need to reexamine the strategies I use in the classroom to both impact the students more and save some precious class time. The Systems Theory approach to Science education is fascinating. Implementation would be a different story however. Our school district is making a move to require the core science classes of biology, geosciences, chemistry and physics in that order. Additional science classes such as environmental science or AP sciences will become electives. This change comes from a task force that met and recommended that the classic sciences be taught in better preparation for college level courses. This means less integration and more stand alone subjects. I am hoping I can get my department to work collaboratively so that we can integrate GCC and other key topics throughout their subjects. I would hate to see GCC relegated to a 4 week unit in Geoscience or a few weeks in Biology while they are studying ecology. It would be a major disservice to students.
I have gained an incredible number of resources by taking this GCC course. The simulations from the PhET site can easily be worked into an activity they can do at home. The NASA climate change site has some very useful information in a highly interactive format that will also catch the students’ imaginations and provide them with more information. With the amount of resources from this course alone, I can integrate more impacting information on the GCC topic. I am rethinking some of my techniques and realize that with the time constraints I have, I need to introduce this topic much earlier on in the year and somehow weave it as a thread throughout the entire school year. I am always telling my students we are the caretakers of the planet and try to get them to take more proactive steps in improving their carbon footprint. I am now thinking perhaps a weekly or biweekly presentation by the students ( lab group presentation) of current forcings and feedbacks both local and global to coincide with the current events happening at that same time. It wouldn’t take much time at all and  it beats having the teacher standing up there lecturing to them on the topic J J How do I bring in all this exciting information with the small amount of time I have to dedicate to the topics?That is something I really need to think about.