Lab 7 – Climate Change Proxy
A proxy is an indicator used to measure whether the world’s temperatures are rising or whether the climate is changing. Scientists use data from various sources to uncover whether climate change has occurred. This essay from the National Oceanic Atmospheric Association change explains the types of proxies scientists use. Because it may be happening over the course of decades, if not centuries, scientists have to rely on historical data. The following dataset shows the duration of ice days calculated as the average number of days that ice covered Cazenovia lake over the time period from 1844-2009. Ice duration is calculated from the day of first freeze over to the day of ice break up and subtracting the number of days the lake was open between the first day of ice coverage and ice-out. These data were collected by the Cornell Biological Field Station as part of their DataStar Project (Rudstam, Lars G. and James R. Jackson. 2011).
Graph the data following the instructions and then answer the following questions:
Step 1: Click on and highlight the two columns of data.
Step 2: Click on Insert and choose line graph from the choices of graphs
Step 3: Click on the title and provide a title for the graph: Ice Cover Caz Lake, choose chart elements and add the titles for the axis – Decade, Average # Days and then submit the excel file along with the answers to the following questions.
1) What is the trend in ice cover for Cazenoiva Lake over the last century?
2) Given what you learned about the physical and biological properties of water speculate: what other factors might cause the trends in ice cover data to change over the past century? (you may want to review the physical characteristics of water and terrestrial plants).
3) Which proxy do you think would be more accurate to determine global climate change? The ice cover data or the data on blooming times collected by the scientists mentioned in the NPR study we listened to in this module? Why do you think this? Give reasons based on your research into what causes ice to melt on lakes, and what may impact blooming times from the discussions. Cite your sources for full credit.
