Tuesday, August 4, 2009

When did the warming start in Alaska

I just came back from Alaska, which is why I had pre-written many of the last few posts. As we drove from an area south of Mount Denali (McKinley) to the north edge of Denali Park, we passed the Alaskan continental divide. South of this line water flows south. North of it, water flows north. The divide is just below the 2700 ft treeline, being at 2400 ft. I noticed few trees, but some of them were tall. This gave a way to estimate when this site became warm enough to grow trees.

The reader should know that as the world warmed, coming out of the Little Ice Age (LIA), the treeline (the elevation at which trees can no longer grow) rose in height, meaning that areas which could previously not sustain tree growth could after the earth warmed as it left the LIA behind. The question is, when did this warming begin?

At the Alaskan continental divide on the road from Anchorage to Fairbanks, elevation 2409 ft, we saw few trees, but some of them were approximately 30 ft high. This raised the possibility of knowing how long ago this area became capable of supporting trees if one could know the growth rate.

As it happens, the son of my next door neighbor is a prof a the University of Alaska. While he was visiting his parents a year ago, he told me that the growth rate of trees was quite small, being of the order of inches per year. Since I don't want to drag him into this fight as an authority on tree growth, I will present my own evidence for the age of these trees. Below are two pictures of this year or last year's growth on White Sprice trees at this elevation. One can see that the annual growth for segments of the tree are between 1.5 and 2 inches.

Given that growth rate information what are the heights of the trees at the continental divide? The tallest, is about 30 ft tall, or about 360 inches. Dividing this by 1.5 inches per year and 2 inches per year respectively, it means that this area became capable for the growth of trees 240 years ago---long long long before the CO2 began to rise. This means that warming started BEFORE the CO2 rose, giving the lie to the widely propagated idea that CO2 is causing the current warming.

Those who claim that modern society with its CO2 emissions is the sole cause of warming are ignoring much data that could show that they are entirely wrong.


  1. 240 years ago puts it around 1760-70 .
    Yearly averaged sunspot numbers 1610-2000.

    Matches up well with the gross sunshine record.

  2. Maybe Al Gore should be campaigning against sunshine!