Katharine’s Northeast Climate Impacts Assessment
Katharine Hayhoe runs ATMOS Research & Consulting, a company that carries out climate change related research. In collaboration withe the Union of Concerned Scientists, they helped to produce the Northeast Climate Impacts Assessment in 2007. (The Northeast in this case covered New England, New York, New Jersey and Pennsylvania, although the NCDC generally includes Delaware and Maryland as well).
The study made some wild claims about temperature rises of up to 14F by 2100, no doubt predicated on similarly unrealistic increases in global temperatures. However, I am more interested in the claims about changes that have already been occurring.
Changes consistent with global warming are already under way across
the Northeast. Since 1970, the region has been warming at a rate of nearly
0.5oF per decade. Winter temperatures have risen even faster, at a rate of
1.3oF per decade from 1970 to 2000. This warming has been correlated
with many noticeable changes across the Northeast, including:
• More frequent extreme-heat days (maximum temperatures greater than 90°F)
• A longer growing season
• Earlier leaf and bloom dates for plants
• Shifts in the mating cycles of frogs to earlier in the year
• Earlier migration of Atlantic salmon in northeastern rivers
• An increase in heavy rainfall events
• Earlier breakup of winter ice on lakes and rivers
• Earlier spring snowmelt resulting in earlier high spring river flows
• Less precipitation falling as snow and more as rain
• Rising sea surface temperatures and sea level
• Reduced snowpack and increased snow density
But how do these claims stand to critical analysis? Experienced Hayhoe watchers will, of course, immediately be suspicious when they see 1970 used as the base point for temperature trends, as the NCDC graph below shows.
Annual 1911 – 2010 Trend = 0.07 degF / Decade
1970 was in the middle of a much colder interval, but the trend over the last 100 years shows only a minor increase of 0.07F/decade, nothing like the alarmist 0.50F/decade, which is used as proof of global warming. The trend since 1931 is much smaller still, amounting to just 0.02F/decade.
What about the “extreme heat” days, that the Report claims to be more frequent? To check this out, I have selected three rural USHCN stations in Maine, New York and Pennsylvania to look at in more detail, Millinocket, Elmira and Uniontown. One of the graphs on NOAA’s website shows the distribution of daily maximum temperatures year by year at each station, as below.
It is clearly nonsense to pretend that there is any trend to more frequent days over 90F, or, for that matter in the percentile distribution. Another useful way to look at maximum temperatures is shown below for Uniontown.
Bearing in mind that the scale for the left hand graph (1931-40) goes up to 110F instead of 100F, it is clear that there were many more days above 90F in the 1930’s (and indeed days above 100F).
As there has been virtually no warming since the 1930’s, I am thoroughly confident that todays frogs are doing pretty much what their granddaddies did 80 years ago.
Tomorrow we’ll see whether the claims about rain and snow stand up to scrutiny. (No prizes for guessing the answer).