Wildfires, Pine Beetles and CAGW/Climate Change Part 2
September 24, 2010Posted by on
Back at the beginning of Sept there was two wildfires in Colorado, one of which the Fourmile Canyon fire got major media attention in the US which brought about people looking to tie it to Global Warming/Climate Change/Climate Disruption or whatever they are calling it this week. That led me to making this post here: https://boballab.wordpress.com/2010/09/12/wildfires-pine-beetles-and-cagwclimate-change/ . Now I finally got things straightened out and some time so here is part 2 of the series.
As shown in Part 1 the assertion is that AGW/Climate Change is causing longer summers in the Rockies and thus causing an increase in Pine Beetle population. This in turn leads to more forest area being vulnerable to wildfires.
Here in step one I used the USHCN Web Interface based on a Google maps to find which stations are in and around the wooded areas of Colorado. There is 13 stations that meet that criteria in the USHCN database and thus in the NASA GISS dataset which is the one I will be using for this look at temperatures. Of those 13 stations only 12 are usable, one station (Collbran) data stops in the year 2000 the others all reach to 2008 or 2009.
Here in figure 1 we see the GISS 250km smoothing grid cell trends and they range from about .5° C to a little over 1° C of warming from 1880 to 2009. Couple things of note:
- The years 1998 to about 2005 appear have a flat trend but well above the baseline of 1951-80, even though there is variations in the amount.
- The tears 2006 to 2009 show a sharp drop all the way back to baseline
What we can say from the grid cell numbers is that overall there has been a warming trend with a period of elevated temperatures for about 7 years followed by a rapid cooling in the last 3 years, which means there is nothing concrete to refute or back up the premise that Pine Beetles are larger in numbers due to longer summers. So lets look at the NASA GISS seasonal numbers for each station, however I will not be putting them all in the same graph. I will separate first by Urban and Rural, then inside the Rural stations by start date (Some stations start around 1895 others around 1903, 1909 and one in 1920)
Here in Figure 2 we have the summer seasonal temperature trends for the three Urban stations of Boulder, Ft. Collins and Canyon City. What we see by the numbers is that the summer season has gotten warmer in the Urban areas since 1895 by about .75° C to .85° C. We also see that while there was some very individual hot years in the 2000’s there was no flat trend of elevated temperatures as seen in the Grid Cell trends. Matter of fact the summer of 2009 was well below the baseline and comparable to temperatures seen in the early 1900’s.
Here in Figures 3 through 6 we have the Rural Stations and below in Table 1 we have the listing of their trends
|Gunnison 3S||1.75° C|
|Fruita 1W||.25° C|
|Hermit 7ESE||.65° C|
|Montrose #2||.5° C|
|Dillon 1E||.2° C|
|Steam Boat Springs||.75° C|
|Telluride 4WNW||1.95° C|
|Del Norte 2E||.5° C|
As you can see some got cooler while the majority got warmer by various amounts over the years, however the 2009 summer temperatures for most of the stations are at or below baseline.
With that all said it still doesn’t give evidence for or against the premise that summers are longer now then in the past. For that we will have to check the trends for the months of May and September to see if they have been going up (and providing evidence that summer is coming sooner or staying later) or going down (and providing evidence that summers are getting shorter).
Here in Figure 7 we see that for the three urban areas Summer appears to be coming earlier since all three have warming trends, with the past decade mostly above baseline.
Here in Figures 8 through 11 we have the Rural trends for May. The numbers are listed in Table 2
|Gunnison 3S||2.25° C|
|Fruita 1W||.9° C|
|Hermit 7ESE||.5° C|
|Montrose #2||.9° C|
|Dillon 1E||-.3° C|
|Steam Boat Springs||.1° C|
|Telluride 4WNW||2° C|
|Del Norte 2E||.5° C|
Here we see some stations cooling but the majority showing a warming trend for the month May, ie that May’s are getting warmer over time, thus making Summer come earlier. Now that is evidence that maybe the premise is correct however it is not definitive yet, we still need to check September. While May’s are showing a warming trend what if Septembers are sowing a cooling trend? If that is the case then Summer’s are not getting longer there is a seasonal shift occurring, however that might play a factor in another part of the Pine Beetle Life Cycle.
Here in Figure 12 we see that Summer is ending sooner in 2 of the three Urban stations with one showing a slight warming in September. Overall the slight cooling trends do not offset completely the May warming trends in those Urban areas.
Here is Figures 13 through 16 we see the trends for the Rural stations. The numbers are listed in Table 3.
|Gunnison 3S||.85° C|
|Fruita 1W||.025° C|
|Hermit 7ESE||.3° C|
|Montrose #2||.2° C|
|Dillon 1E||-.55° C|
|Steam Boat Springs||.75° C|
|Telluride 4WNW||1.1° C|
|Del Norte 2E||-.1° C|
So we see again some cooling with the majority showing warming, thus showing a longer summer in the majority of Colorado stations. This fits part of the premise that summer are longer, but does it really explain the increased population of Pine Beeltles. According to the Wiki article if the temperatures get cold enough for a specific amount of time during winter, it will kill the larvae of the Pine Beetles, so it would follow that if the Winter season was getting warmer you would get more surviving larvae that will turn into Beetles in the spring and thus lay more larvae, increasing population. That in turn would mean more trees would get Beetle infestations, so we need to check the Winter temperatures to see if that is the case.
Here in Figure 17 we see that the three Urban stations show warming trend for winter with most of the past decade well above baseline.
Here in Figures 18 through 21 we have the Rural Winter trends. The numbers are in Table 4.
|Gunnison 3S||3.5° C|
|Fruita 1W||2.3° C|
|Hermit 7ESE||-.2° C|
|Montrose #2||1.1° C|
|Dillon 1E||1.9° C|
|Steam Boat Springs||1° C|
|Telluride 4WNW||.5° C|
|Del Norte 2E||-.2° C|
Now some of the stations show a cooling trend but most show a warming trend, thus lending weight to the counter hypothesis that it is warmer winters that have been the reason for a larger Pine Beetle population. However there is a problem with those warming trends: They don’t tell us if the temperatures are actually above the temperature that is the larvae kill point, so we need to look at that. So first we need to go back and get the actual temperatures for the stations with warming trend and then instead of making our anomalies by using a 1951-80 baseline, we base them on the kill point temperature. This means a trek into the USHCN Daily temperature database to get the reading for each winter day over the years. This also is good place to break off this really long post and do that in Part 3.
NOTE: The wiki article has a line that is a incorrect statement based on the link they even provided (Incorrect part bolded):
It is largely believed that temperatures down to −30 °C to −40 °C (−22 °F to −40 °F) for at least several days, or at least twelve hours of −40 or lower, kills most mountain pine beetles. This is not a true statement.(Logan and MacFarlane, Figure 2, http://www.actionbioscience.org/environment/loganmacfarlane.html)
When you click on that link and look at the graph, you see that Figure 2 is graph of a model run, not observation, but it still shows that if the temperature is cold enough it kills off the Beetles. Also if you read the accompanying text you see that the NGO document agrees with the wiki article about temperatures:
Winters are becoming mild enough that even adult beetles, a freeze-intolerant stage, are surviving.