Climate Changes Disrupt in Seasons

In the United States and all across the world non-biological seasonal shifts are occurring due to the warming trend. Many of the budding signs in spring are arriving earlier, summers are warmer, winters are shorter, and the leaves are falling sooner in fall (8).

In southern New England the yearly precipitation rate has increased by more than 25% since the past century. Snowfall in northern New England has decreased by 15% since 1953. New England snow lies on the ground for seven days less each year than it did 50 years back (3). Snow-melt in the Western U.S. Is occurring four weeks earlier than it did in the mid 20^th century (8).

Today 30% of the Earth's surface is affected by drought, compared to 10 to 15% 35 years ago. Scientists are mostly blaming this change on the increase in temperatures.

During the past 40 years snowfall has decreased by 30% in Australia, causing the winter season to be shorter

Another change in the season is that the lakes in Pennsylvania on average freeze about 10 days later than they did 50 years ago and thaw around 9 days sooner.

In Europe the vegetative growing season of trees, shrubs, and herbs has risen by 11 days since 1960.

The oak trees in England are leafing two weeks earlier than they did 40 years ago, another piece of evidence that season lengths are changing (3).

You might be wondering does it really matter if the ice melts sooner of the flowers bloom early? Well, it does. Changes in phenology (the relation between climate and periodic biological phenomena) in one species has major impacts throughout the ecosystem. For example, when the warm spring weather causes the plants to bloom earlier, it upsets the life cycle of insects that rely upon them for food. This occurs further up the food chain with other species. If a species does not adapt, the chain is broken, and this is when the number of species starts to disappear (8).

Crop Yield Gains & Losses

The increasing temperature due to global warming has caused farmers to lose their crops. This has been occurring for over 25 years.

David Lobell of Lawrence Livermore National Laboratory in Livermore and Christopher Field of the Carnegie Institution in Stanford are two ecologists in California that have designed a statistical model. This model combines "worldwide temperature, rainfall, and yield data from 1961 through 2002 for the world's six most planted crops--barley, corn, rice, sorghum, soybeans, and wheat" (5).

During these four decades total crop yields were almost double. However Lobell and Field explained that as global temperatures were rising in the 1980's, the excess heat slowed down the growth of the crops. In 2002, approximately 40 million tons of barley, corn, and wheat were being lost each year. Due to this problem the price of crops has gone up.

Carbon dioxide a primary cause of global warming, is having the opposite effect on crops. Rising levels of carbon dioxide increase crop yields. Lobell and Field believe that the crop "yield gains from higher carbon dioxide levels were roughly equal to the losses from heat" (5). In the future what will happen is that the positive impact of climate change on vegetation production might reverse (5, 6). Climate changes occur in cycles (5). For the next couple of decades we are in good shape (5, 6).

Wildfires, Warmer Rivers, Wetlands

The increase in warmer, drier temperatures has also increased the number of wildfires in western forests. Some examples of states hit hard are Montana, Wyoming, Utah, and New Mexico.

The warmer weather has also raised the temperatures of streams and rivers which has damaged the proper habitat for trout, salmon, and other kinds of cold-water fish in the West. The suitable habitats by the Rocky Mountains could decline 50% if average temperatures in July rise 5.4 degrees Fahrenheit.

Wetlands are in danger due to global warming. Specifically the Prairie Pothole Region's wetlands could reduce at most 91% by the 2080's, which would result in a 69% reduction of the ducks that breed there. Global warming is estimated to reduce about 30% of perennial grasses and forbs as well as 17% loss of shrub species.

Ways to take Action
As you all may know there are energy efficient technologies out there available for homes, cars, buildings, and appliances. Furthermore clean, renewable energy sources such as the sun, wind, and biofuels are up and coming. These new exciting sources of energy will greatly improve our environments. Here are some ways to take action:

1. reduce the dependence on fossil fuels
2. invest in energy efficient and renewable energy sources
3. put forth strategies that will help the wildlife from global warming
(targetglobalwarming.org)

Global Warmings effect on Snowpack, Drought, and Sagebrush

Global warming’s effect is causing snowpack to reduce, which poses problems on certain region’s water supply. Mountains located in the Pacific Northwest are estimated to lose as much as 88 percent of its average snowpack by 2090. The Central Rocky Mountains are estimated to lose up to 75 percent, and sections of the Southern Rockies and the Sierra Nevada are estimated to lose 98-100 percent (targetglobalwarming.org).

A Rocky Mountain meadow located between snowy mountains has been watched by scientists for almost three decades. Until 2000 the meadow seemed to be resisting the effect of global warming even though spring had arrived earlier. It was covered in a white blanket of snow. After 2000 the meadow was thriving because of a drought that had reduced the amount of snowfall (nationalgeographic.com).

In general drought will probably become more extreme in some regions as the average temperatures increase which adds to raised evaporation rates. The drought affecting the West is the worst seen in 500 years and has immensely lessened the water resources available for people and wildlife (targetglobalwarming.org).

An ecologists study has shown that snow has begun to melt earlier as well as the soil drying sooner. When the soil is drier it stores less carbon, and less carbon in the soil means that there is more in the atmosphere. He said that this will increase the rate of global warming (nationalgeographic.com).

Sagebrush, a common shrub found in the West prefers drier soil. It has been dominating the meadows in the Rocky Mountains and pushing out wildflowers. He also believes that the five years of this drought has been consistent with global warming (nationalgeographic.com).



image from: http://www.scsc.k12.ar.us/1999Outwest/members/LachowskyR/Big_Sagebrush.jpg

Resources

1.
http://news.nationalgeographic.com/news/2005/04/0411_050411_rockiesspring.html
(I chose this website because it had good evidence for season length changes.)

2.
http://www.targetglobalwarming.org/fuelingthefire
( I chose this article because it has good information about snow packs, droughts, wildfires, and wetlands.)

3.
http://search.ebscohost.com/login.aspx?direct=true&db=sch&AN=16621621&site=ehost-live
(I chose this website because it emphasized how seasons have changed over the years.)

4.
http://search.ebscohost.com/login.aspx?direct=true&db=sch&AN=27341071&site=ehost-live
(I chose this website because it gave evidence about certain plants that are in danger because of global warming, and what needs to be done with this issue.)

5.
http://search.ebscohost.com/login.aspx?direct=true&db=sch&AN=25066810&site=ehost-live
(I chose this article because it examined the effect of global warming on the most widely planted crops.)

6.
http://news.nationalgeographic.com/news/2003/06/0605_030605_climatechange.html
(This article did a good job at discussing how climate change has influenced global vegetation.)

7.
http://www.cleartheair.org/documents/SeasonCreep.pdf
( This was an excellent article on how climate change is disrupting the seasons.)