Mick, I need a really smart answer to a really stupid question. How can I represent climate change in Maine either by weather patterns or bird migration or water levels or what? It need to be something local and measureable and preferably visual. Hopefully, XXXXXXX
___________________________________________
From: Mick Womersley
Sent: Sun 4/6/2008 6:37 AM
To: XXXXX
Subject: RE: climate change
Dear XXXXX
So far, Maine's climate change impacts are complex but quantifiable and some are statistically significant.
On average spring is earlier and summers are now warmer. Precipitation has increased, including snow, which has recently, I feel, lent some people to mistakenly believe that winters are getting colder when they're more likely just slightly whiter.
The earlier spring is local and certainly measurable. Earlier ice-out days on rivers and lakes are also quite distinct and statistically significant if you use time-series regression analysis.
I feel we will eventually find that statistically speaking this seemingly hard winter and seemingly late spring are still within the reasonable boundaries of a warming trend, ie, not an outlier. Climate statistics are related to weather statistics in much the same way your idea of the balance of your bank account is related to the actual number on the statement when it comes in -- until you do the math, it's always not what you think.
Here are some links with the data you seek:
Ice-out study: http://pubs.usgs.gov/fs/2005/3001/
Evidence for early spring: www.cleanair-coolplanet.org/documents/spring.pdf
1 comment:
Here's a statistical report I did in 2005. Contact me for figures and appendices.
Abstract
Ice-out dates from eight lakes were analyzed to determine the effects of climate change on lakes in Maine. Statistical analysis was done to determine if there were significant differences among the mean ice-out dates of the lakes in the past century. Lakes in Southern Maine have ice-out dates an average of 12 days earlier this century than last. Lakes in Central Maine have ice-out dates an average of 5 days earlier this century than last. 12 days was found to be a significant difference while 5 days was not. The results of southern lakes in Maine support the claim that climate change is affecting lakes, but the results of central lakes in Maine do not.
Introduction
Climate change is the change in global climates due to heat being trapped in the earth’s atmosphere. Pollution from burning fossil fuels creates the shield that traps heat (Berk).
Scientists are in consensus that climate change is occurring. It is occurring very quickly because of our polluting habits (Berk; International, 2001). The Climate Change Synethesis Report states that a decrease of about two weeks in the duration of ice cover on lakes over the 20th century in the mid to high latitudes of the Northern Hemisphere is very likely (International, 2001).
Research done in the New England area shows that ice-out dates are occurring earlier than they did a century ago (Berk; United, 2005). The New England Regional Assessment, “Overall the region has warmed by 0.7°F…[yet] Maine has cooled [between 1885 and 1999] (International, 2001). Observations have revealed that Maine is having more heat waves, more droughts, more asthma due to smog, more coastal flooding, and less maple syrup than a century ago (Berk).
This research has lead to the claim that Maine lakes are being affected by climate change. All hypotheses were tested to the 0.05 level of significance. The hypothesis is that there is a significant difference among the mean ice-out dates of lakes in Maine. The null hypothesis is that there is no significant difference among the mean ice-out dates. The first hypothesis tested is for Hartley’s Test: there will not be a significant difference among the variances of the ice-out dates. The second hypothesis tested is for the F-ANOVA test: there will not be a significant difference among the means of ice-out dates. The claim associated with Tukey’s Test is that there will be a significant difference between the mean ice-out dates of the 19th century and the 20th century.
Methods
Data was collected for eight lakes in Maine: four in Southern Maine and four in Central Maine (Figure 1). Dates were obtained from the United States Geological Survey (USGS) and were observed by many (Hodgkins & James, 2002). Lakes in different regions of Maine have significantly different ice-out dates, thus the separation of lakes in Southern and Central Maine. The ice-out dates were entered into Excel as 3-digit dates for each year. Each lake was presented on a separate spreadsheet, and each region was presented in a separate workbook.
Then, data was analyzed using Descriptive Statistics to find the mean, standard deviation, minimum and maximum dates, and the number of years recorded. Three different analyses were done for each lake: Descriptive Statistics was done for all dates, dates in the 19th century, and dates in the 20th century.
In a separate spreadsheet, for each region, the mean ice-out date for each group of years was found from all the means of lakes. The minimum and maximum dates, and the variance and standard deviation were also determined. In this same spreadsheet, Hartley’s test, F-ANOVA, and Tukey’s test were all reported.
Hartley’s H was found by dividing the maximum variance by the minimum variance. The critical value was determined from the observed degrees of freedom and with the use of a table (Hartley’s, 1952). After it was shown that there was not a significant difference among the variances, the F-ANOVA test was conducted. This was done in MiniTab, and the p-value was recorded in the Excel spreadsheet. If it was shown that there was a significant difference among the means, then Tukey’s test was done. Tukey’s was also calculated in MiniTab and recorded in Excel.
Results
There was not a significant difference among the variances of southern lakes. There was a significant difference among the means. Tukey’s test revealed that the mean of the 19th century significantly differed from the mean of the 20th century. At the 0.05% level of significance there was a significant difference between the means of the 19th and 20th century. The change in ice-out dates over time can be seen in Figure 2. The raw data for Southern Lakes is in Appendices A and B.
There was not a significant difference among the variances of central lakes. There was no significant difference among the means; therefore Tukey’s test was not done. At the 0.05% level of significance there was not a significant difference between the means of the 19th and 20th century. The change in ice-out dates over time can be seen in Figure 3. The raw data for Central Lakes is in Appendices C and D.
Discussion
The analysis of the lakes in Southern Maine show significant difference in the mean ice-out dates. A 12 day difference between the mean ice-out date of the 19th century and the mean ice-out date of the 20th century is a significant difference. This analysis supports the claim that climate change is affecting lakes in Maine.
The analysis of the lakes in Central Maine show no significant difference in the mean ice-out dates. A 5-day difference between the mean ice-out date of the 19th century and the mean ice-out date of the 20th century is not a significant difference. This analysis does not support the claim that climate change is affecting lakes in Maine.
Since there was limited data for the lakes in northern Maine, it is suggested that further research be done to determine the ice-out dates for the northern lakes to conclude whether the northern lakes are being affected by climate change. It is also suggested that more lakes be analyzed to determine the affects on the Northeast region as a whole. Finally, it should be stated that difference in ice-out dates alone cannot determine whether or not climate change is affecting Maine; many other factors should be taken into account.
Acknowledgements
Data was observed by many and collected by the USGS. Lakes not mentioned hereafter were obtained from the USGS (Hodgkins & James, 2002). Kennebec Water Power Company, and Maine Department of Inland Fisheries and Wildlife: Moosehead Lake. Maine Sunday Telegram, Carroll Cutting, and Portland Press Herald: Sebago Lake.
Post a Comment