Guest Columnist
Scientists determined 150 years ago that the 100th Meridian (eastern side of Texas panhandle) was a firm boundary between the humid eastern and arid western parts of the U.S. This line establishes major changes in natural vegetation, weather (temperature and rainfall), and agriculture.
This line was stable for centuries, but in the past 39 years, climate change caused it to move some 140 miles east to the 98th Meridian, which is approximately 75 miles west of Dallas. The line is projected to move to the 96th (just east of Greenville) or 95th (approximately Mt Vernon) Meridian by end of this century. Implications of this line continuing to move east are ominous in terms of rainfall, crops grown, and forest types.
Much of our solar heat would radiate back into space if not for water vapor and greenhouse gases. Carbon dioxide (CO2 - a greenhouse gas) concentrations are the highest in 650K years. The annual U.S. temperatures for the last 20 years have all been above the 20th century average. Climate zones have increased their temperatures by 5°. Last (spring) killing frosts are coming earlier, with first killing frosts (fall) coming later. Growing season has expanded by two weeks, with most of the expansion in the last 30 years.
Surface temperatures have grown 1.3° over the last century, with much of the rise in the last 20 years. The tipping point from which there is no return is thought to be 2° Celcius, and surface temps are projected to grow anywhere from 2-6.5° by the end of this century. While an additional 1° rise will cause major agriculture changes, higher rises will result in a new climate with more major floods, storms and droughts to go along with rising sea levels. The new climate could last as long as 200+ years.
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