Changing landscapes can alter weather patterns
Since my column last week that featured the fires in the Amazon rainforest, there were approximately 2,000 new fires that broke out in 48 hours. In South America, Brazil has reported nearly 90,000 fires from January through August and over half of them were located in the precious rainforests.
The majority of these blazes have been started by people clearing the land for agricultural and cattle usage. According to data from the University of Maryland, approximately 30 million acres of land in this part of the world was cleared of trees, which included nearly 9 million acres of rainforests.
According to an article by National Geographic, forests cover about 30 percent of the world’s land area. But, forests are shrinking fast as over 500,000 square miles have disappeared between 1990 and 2016. About 17 percent of the Amazon rainforest has been cleared over the last 50 years.
The different species of trees are extremely important to the Earth’s natural systems. They do provide some oxygen as well as storing carbon and stabilize the soil. It’s estimated that our planet has about 3 trillion trees, yes trillion. However, according to The North American Forest Commission, the U.S. has roughly two-thirds of trees when compared to the year 1600.
In recent years, the U.S. has made major strikes in adding trees. Unfortunately, other parts of the world, humans are cutting down trees, especially tropical ones that are crucial to vital ecosystems. Across the planet, it’s estimated that 15 billion trees are cut while only 5 billion are replanted.
There are studies that show that weather patterns are being altered by the clearing of trees. According to research by the Australian government, land clearing in Western Australia resulted in that region’s decrease in rainfall in recent years.
Other research points out that deforestation in the immediate area can lead to increased rainfall. But, over a wide area where tree-clearing has occurred, precipitation amounts have shown to be decreasing as desert areas in Africa and other parts of the world are expanding.
Here in Idaho, over 60 percent of our land is covered with forests, mostly in the mountain locations. Our state has mostly conifers or pine trees along with a few deciduous trees. Our state tree is the Western White Pine which is found mostly in the forests of northern Idaho.
The trees in our region do help reduce wind speeds and cool the surrounding air. There can be a difference of about 10 degrees, especially during the summer season, in areas with more trees versus ones with wide open spaces. They can also reduce the water runoff from storms and the effects of flash floods. And, of course, trees provide protection and food for many birds and mammals.
In terms of our local weather, Cliff and I believe we’ve seen the last of the very warm days for 2019. Last Thursday, high temperatures were in the upper 80s to around 90 degrees across North Idaho. At Cliff’s station, the mercury hit a toasty 88 degrees.
For the summer of 2019, there were 10 days with high temperatures at or above 90 degrees. However, there were 22 days with readings in the mid to upper 80s. We didn’t hit the 100-degree mark as the hottest days of the summer were on July 23 and Aug. 8 with a high of 97 degrees. Despite a few smoky days, the summer season across North Idaho and the rest of the Inland Empire was pretty good.
Our summer’s precipitation was below normal, but better than the last several years. For June, Cliff measured 1.62 inches, compared to a normal of 1.93 inches. July only had .62 inches, which was .30 inches below the average. August ended up with .98 inches of moisture, a little below the normal of 1.23 inches. Last year, the total precipitation for the summer was 2.32 inches as only 0.04 inches fell in July of 2018.
In the waters of the south-central Pacific Ocean, sea-surface temperatures are still cooling. We wouldn’t be surprised to hear about a new cooler “La Nina” declared late this year. With very little solar activity, the chances of a snowier than normal winter are higher. In fact, there were only two within the last 30 days, Sept. 1 and 2, that there has been any sunspot activity.
After the wet weather early this week, conditions are looking drier than normal until we get toward the middle to the end of the month. I still believe that our precipitation total for September will be close to the normal of 1.48 inches. Last year, we only had 0.38 inches of rain at Cliff’s station in Coeur d’Alene. Conditions are expected to turn wetter than normal as we move into the fall season with above average moisture totals forecast for the winter of 2019-20. And, as usual, time will tell.
- • •
Contact Randy Mann at randy@longrangeweather.com