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5.1: Biodiversity

Difficulty Level: At Grade Created by: CK-12
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Understanding Biodiversity does not attempt to provide a complete review of climate change. For additional information about climate change, see the Communities and Populations chapter in the CK-12 Biology FlexBook at http://www.ck12.org/flexbook/book/2537 and the Ecology and Human Actions chapter in the CK-12 Biology I - Honors FlexBook at http://www.ck12.org/flexbook/book/829.

Does global climate have an effect on biodiversity? How could it not?

A major problem caused by increased air pollution is global climate change. Global climate change refers to a worldwide significant and lasting change in the distribution of weather patterns over periods ranging from decades to millions of years. This change may be a change in average weather conditions or the distribution of events that influence the average weather conditions.

What causes this change? It is probable that gases such as carbon dioxide from the burning of fossil fuels increase the natural greenhouse effect. This raises the temperature of Earth’s surface. This has numerous consequences. Does this climate change affect biodiversity? Of course it does. And probably in a negative fashion.

What Is the Greenhouse Effect?

The greenhouse effect is a natural feature of Earth’s atmosphere. It occurs when gases in the atmosphere radiate the sun’s heat back down to Earth’s surface (see The Greenhouse Effect Figure below). Otherwise, the heat would escape into space. Without the greenhouse effect, Earth’s surface temperature would be far cooler than it is. In fact, it would be too cold to support life as we know it.

The Greenhouse Effect. Without greenhouse gases, most of the sun’s energy would be radiated from Earth’s surface back out to space.

Global Warming

Global warming refers to a recent increase in Earth’s average surface temperature (see Global Temperatures Figure below). During the past century, the temperature has risen by almost 1°C (about 1.3°F). That may not seem like much. But consider that just 10°C is the difference between an ice-free and an ice-covered Earth.

The average annual temperature on Earth has been rising for the past 100 years.

Most scientists agree that global warming is caused by more carbon dioxide in the atmosphere. This increases the greenhouse effect. There is more carbon dioxide in the atmosphere mainly because of the burning of fossil fuels. Destroying forests is another cause. With fewer forests, less carbon dioxide is removed from the atmosphere by photosynthesis.

Effects of Climate Change

How has global warming affected Earth and its life? Some of its effects include:

  • Decline in cold-adapted species populations, such as the polar bears.
  • Melting of glaciers and rising sea levels.
  • Coastal flooding and shoreline erosion.
  • More droughts and water shortages.
  • Changing patterns of precipitation.
  • Increasing severity of storms.
  • Major crop losses.

With Deaths of Forests, a Loss of Key Climate Protectors, (http://www.nytimes.com/2011/10/01/science/earth/01forest.html) published October 1, 2011 by the New Your Times, discusses the effects of shrinking forests on the global climate. Forests remove greenhouse gases from the atmosphere, and with shrinking forests, less of these gases can be removed. Scientists state that to ensure that forests are preserved for future generations, society needs to limit the fossil-fuel burning that is altering the climate of the world.

In November 2011, the Nobel Prize-winning Intergovernmental Panel on Climate Change issued a special report on global warming and extreme weather (http://news.yahoo.com/science-panel-ready-extreme-weather-104156773.html). They warned of more severe droughts, floods and heat waves due to the warming world. They went on to further say that without proper preparedness, crazy weather extremes may overwhelm some locations, making some places unlivable.

KQED Quest: Climate Watch: California at the Tipping Point

The world's climate is changing and California is now being affected in both dramatic and subtle ways. In 2008, scientists determined that California’s temperatures increased by more than 2.1°F during the last century. What’s more, the data showed that human activity has played a significant role in that climate change. “What's just 2 degrees?” you may wonder. But, as the science shows, just 2 degrees is extremely significant.

What does all this temperature change mean? For starters, declining mountain snowpack and prolonged drought conditions could pose a threat to limited water supplies. Heat waves are projected to be longer, bringing increased danger from wildfires and heat-related deaths. Rising sea levels due to temperature shifts jeopardize life in coastal areas, both for human communities and the plants and animals that rely on intertidal and rich wetland ecosystems. Also, more precipitation is expected to fall as rain rather than snow, thereby increasing the risk of floods. And, as heat increases the formation of smog, poor air quality could get even worse.

Climate change may also profoundly affect the economy in California and elsewhere. Shorter ski seasons and damage to the marine ecosystem mean a reduction in tourism. Water shortages mean issues with the commercial and recreational fishing industry, and higher temperatures will affect crop growth and quality, weakening the agricultural industry, to name just a few of the economic issues associated with climate change.

Get an in-depth look at the science behind climate change at http://www.kqed.org/quest/television/climate-watch-california-at-the-tipping-point-part-one.

KQED Quest: Giant Redwoods and Global Warming

Forest ecologist Steve Sillett is leading a team of scientists as they climb and measure every branch of some of the last and tallest old growth redwoods in California. Their goal is to learn how these ancient giants have historically responded to climatic shifts and to monitor how they are being impacted today by global warming. See http://www.kqed.org/quest/television/science-on-the-spot-measuring-redwood-giants for additional information.

KQED Quest: Acidic Seas

Melting glaciers, rising temperatures, and droughts are all impacts of global warming. But how does global warming actually affect the oceans? The sea, it turns out, absorbs carbon dioxide emissions. These emissions are causing the oceans to become more acidic. Changing pH levels threaten entire marine food webs, from coral reefs to salmon.

As you can probably guess, the ocean is an incredibly complex system. So ocean acidification poses an interesting question to scientists: what will the impacts be on marine species and ecosystems? What scientists know already is that some creatures will do fine, while others won't be able to adapt in time. Either way, food webs may feel the effects. Clearly, understanding the potential consequences is important.

Another major concern has to do with marine animals with certain kinds of shells. Corals, clams, and others all use carbonate in the water to build their shells out of calcium carbonate. But ocean acidification reduces the amount of carbonate in the water, making it more difficult for them to make shells. That could be devastating for coral reefs, who are already facing a number of stresses. See http://www.kqed.org/quest/radio/acidic-seas for additional information.

What Can Be Done?

Efforts to reduce future global warming mainly involve energy use. We need to use less energy, for example, by driving more fuel-efficient cars. We also need to switch to energy sources that produce less carbon dioxide, such as solar and wind energy. At the same time, we can increase the amount of carbon dioxide that is removed from air. We can stop destroying forests and can plant new ones.


Opening image copyright by carlosdelacalle, 2011. Used under license from Shutterstock.com.

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