Global Warming

 

We hear about Global Warming and Climate Change in the news – from devastating hurricanes to heat events - but what is it and what can we do to help stop Global Warming? Is it bad to do things like drive a car or use electricity? Not if done in a responsible manner. Learn why and how, and more about Global Warming with the information below.


What is Global Warming?

Global Warming is an increase in the near surface temperature of the Earth. It is a term most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases. It is different from the term climate change in that climate change is more broad and refers in the wider sense to also include natural changes in climate. Climate change and global warming have occurred on Earth as the result of natural influences and in cycles throughout the history of the Earth; however, the current warming we are experiencing and that is expected to continue is the result of human-caused increases in greenhouse gases, specifically carbon dioxide. There is more carbon dioxide in the atmosphere now than there has been in the past 650,000 years. The carbon dioxide stays in the atmosphere and acts like a warm blanket that holds in the heat. This phenomenon is called the greenhouse effect.

One thing to keep in mind is that having some greenhouse gasses in our atmosphere is not bad. We do need some warmth on the Earth or we would not have the proper narrow range of temperature that allows us to have the right conditions for breathable air, clean water and mild weather. In fact, the Earth in general would be too cold to inhabit without some greenhouse gasses or the greenhouse effect. However, humans have begun to tip the balance and overload the atmosphere with too many greenhouse gases from our cars, factories and power plants – gasses that trap more heat and can lead to devastating changes in our environment. If we don’t start fixing the problem now, we are in for more extreme temperatures, rises in sea levels and more destructive storms.

Why Should I Be Concerned About Global Warming?

Global Warming affects us all. We only have one planet, one home, that sustains the lives of all of the living things on it. Climate change itself is not bad and is a normal part of our Earth’s history. The difference with the Global Warming we are experiencing now is that it is human-caused and happening at a faster rate than previously predicted by scientists. Global Warming is expected to mean the melting of ice, flooding of coastlines, increased health risks, and more extreme weather conditions and events in our lifetime and the future.

According to the National Academy of Sciences, the Earth's surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. Since the Industrial Revolution, more and more greenhouse gasses have been added to our atmosphere as a result of automobiles, factories and power plants. Because there are uncertainties surrounding Global Warming (e.g., how much warming, how fast, how devastating), it is a difficult topic for some to grasp. What is know with certainty is that human activities are adding greenhouse gasses to the atmosphere, and that these gases have been shown to warm the Earth. The risks that Global Warming poses are real. Because the exact nature of the outcomes is still an unknown, and may not be known for decades, we must use our best judgment guided by what we do know from science to help with our response. Learn more about what is being done to help stop Global Warming.

You will find more information there about the impacts of Global Warming on the following topics:

Water Resources
Polar Regions
Mountains
Forests
Rangelands
Deserts
Non-tidal Wetlands
Coastal Zones
Agriculture
Fisheries
Birds
National Parks
State Impacts
International Impacts

 

I will only cover a few topics which I believe are some of the most critical and most notorious that we get to see and hear so much in the news. The other topics are for you to investigate or perhaps to discuss in your classroom with your teacher.

Water Resources

Changing climate is expected to increase both evaporation and precipitation in most areas of the world. In those areas where evaporation increases more than precipitation, soil will become drier, lake levels will drop, and rivers will carry less water.

Lower river flows and lower lake levels could impair navigation, hydroelectric power generation, and water quality, and reduce the supplies of water available for agricultural, residential, and industrial uses. Some areas may experience both increased flooding during winter and spring, as well as lower supplies during summer. In California’s Central Valley, for example, melting snow provides much of the summer water supply; warmer temperatures would cause the snow to melt earlier and thus reduce summer supplies even if rainfall increased during the spring. More generally, the tendency for rainfall to be more concentrated in large storms as temperatures rise would tend to increase river flooding, without increasing the amount of water available.

Navigation

Climate change could impair navigation by changing average water levels in rivers and lakes, increasing the frequency of both floods during which navigation is hazardous and droughts during which passage is difficult, and necessitating changes in navigational infrastructure. On the other hand, warmer temperatures could extend the ice-free season.


Hydropower

Changes in the flows of rivers would have a direct impact on the amount of hydropower generated, because hydropower production decreases with lower flows. Because of the ambiguous projections of changes in future river flow, studies of the impacts of climate change show ambiguous effects on hydropower production

Environmental Quality and Recreation

Decreased river flows and higher temperatures could harm the water quality of a nation's rivers, bays, and lakes. In areas where river flows decrease, pollution concentrations will rise because there will be less water to dilute the pollutants. Increased frequency of severe rainstorms could increase the amount of chemicals that run off from farms, lawns, and streets into the nations rivers, lakes, and bays.

Flood Control

Although the impacts of sea level rise and associated coastal flooding have been more widely discussed, global climate change could also change the frequency and severity of inland flooding, particularly along rivers.

Polar Regions

Polar regions such as Alaska, the Arctic, and Antarctica contain a wide variety of physical features and ecosystems. The alpine and lowland glaciers, ice caps, sea ice, permafrost, boreal (see glossary) forests, tundra, peatlands, and meadows found in high-latitude regions are sensitive to subtle variations in air temperature, ocean temperature, and other climatic conditions.

Climate models indicate that global warming will be felt most acutely at high latitudes, especially in the Arctic where reductions in sea ice and snow cover are expected to lead to the greatest relative temperature increases. Ice and snow cool the climate by reflecting solar energy back to space, so a reduction in their extent would lead to greater warming in the region.

Many changes already are apparent in high-latitude regions. For example:
* Arctic temperatures during the late 20th century appear to have been the warmest in 400 years.
* Satellite data suggest that the extent of snow cover has declined by 10 percent since the late 1960s.
* During the 20th century, the annual duration of lake and river ice cover in the mid- and high latitudes of the northern hemisphere declined by about two weeks.
* Since the 1950s, the extent of northern hemisphere spring and summer sea-ice decreased by about 10 to 15 percent, and researchers have measured a decline of roughly 40 percent in the thickness of Arctic sea-ice during late summer and early autumn during the past several decades.
* Since the 1950s, Alaska has warmed by an average of 4 degrees Fahrenheit.
* Pine Island Glacier, part of the West Antarctic Ice Sheet, thinned by up to 1.6 meters (5.2 feet) per year between 1992 and 1999.
 
 

Sea Ice

Sea ice regulates exchanges of heat, moisture, and salinity in the polar ocean, and provides key habitat for wildlife.

A loss of sea ice leaves coasts more vulnerable to storm surges and erosion and alters the habitat of marine mammals such as polar bears, ring seals, and beluga whales, possibly affecting their population numbers or distribution.

Satellite data indicate record reductions in regional sea ice cover in recent years. Climate models project large continued losses of sea ice in the future.

 

Wildlife

Researchers reported in 1999 that a decline in the health of polar bears during the past two decades may be linked to rising spring temperatures in Hudson Bay and the early breakup of sea ice. Scientists from the Canadian Wildlife Service determined that polar bears' health may be declining from improper nutrition. Polar bears hunt one of their primary food sources, ringed seals, in the spring months on the sea ice. During the past 20 years, warmer temperatures have led the ice to break up about three weeks earlier in the season. This early breakup leaves less time for the bears to hunt seals and therefore means that they have less food.

Antarctic wildlife also has been affected by climate change, according to William Fraser of Montana State University. Fraser has documented significant declines-approximately 50 percent over the past 25 years-in populations of Adelie penguins near Palmer Station on the Antarctic Peninsula. The declines appear to be caused by regional changes in sea ice and snowfall, which in turn may be related to global climate change.

Forests

Changes in temperature and moisture are expected to have variable impacts on the forests of the high-latitude zones. Northern treelines are likely to advance slowly into areas now occupied by tundra. Forests whose productivity is not limited by the availability of moisture may become more productive as the climate warms, but this may be counterbalanced in some areas by increases in the frequency of fires and pest outbreaks.

Forests that are sensitive to drought may be adversely affected by global warming. For example, white spruce forests in interior Alaska have experienced severe stress from temperature-induced drought during the past 90 years.

Some Alaskan forests have experienced a sustained infestation of spruce bark beetles since 1992. The outbreaks, formerly limited by the cold, have caused the death of 2.3 million acres of trees on the Kenai Peninsula in Alaska. This is the largest loss of trees to insects ever recorded in North America.

 

I hope that little introduction to Global Warning, can motivate you to find out more about the other topics and I hope that you will be able to speak up about this serious situation that we are facing not only in Australia but all over the world. Remember this is our planet, the only place so far that can holds life, so lets all protect it the best we can. Don't be afraid to write letters to your local MP, to find out what they are doing for the environment in our communities.