August 31, 2009
UNIT 5: EcologyGlobal Warming — Changing the Planet
As global temperatures rise and arctic ice melts, polar bears are losing important hunting grounds.
Polar bears are beginning to drown. In the summer, the area of arctic sea ice on which these carnivores hunt seals has declined 10 to 15 percent as worldwide temperatures rise. As this ice is lost, polar bears must swim as far as 100 kilometers (about 60 mi) to find their prey. Some of these polar bears do not make it. If global warming is changing the shape of one of Earth’s coldest regions, how will it affect the rest of our planet?
Ecosystems at Risk
In the 21st century, the average global temperature is expected to rise about 0.22ºC (0.4ºF) per decade. This may seem like a small change, but this change is magnified in the seasonal temperature changes of a region. In some parts of the world, such as the Arctic, the temperature is changing much faster. Average annual temperatures in Alaska have risen 3.3ºC (5.9ºF) since 1949. Sea ice area has been shrinking over the past 100 years, and the ice has become 40 percent thinner in the past several decades, leaving coastal land vulnerable to erosion.
Good and Bad News?
In the rest of the world, the impact of global warming on Earth’s species may not be as bad. Many animal species, such as birds and butterflies, can move to cooler areas as the climate warms. But the microorganisms that cause infectious diseases, such as malaria and yellow fever, are also spreading toward the poles. Plant species are moving as well, but many are not able to move as quickly as the climate is expected to change.
Computer modeling programs such as this one work to predict the effects of global warming by simulating different temperature increases.
Researchers are also finding that changing temperatures can affect animals in surprising ways. The sex of some reptiles, for example, is partially determined by the temperature of the developing egg. A consistent warming trend could cause some reptiles to become extinct by creating entire generations that are all the same sex. Migratory birds and marine mammals also face challenges. For example, birds that wait until their normal migration time to fly north in the spring may arrive too late, missing the best weeks for laying eggs and catching the insects they need to raise their young. In addition, marine mammals face challenges in their own food webs. Several researchers are predicting that the productivity of phytoplankton, the algae on which ocean food webs are based, may decline in some areas. A change of this sort could cause a domino effect in marine food webs. If phytoplankton levels decline, fish will have less food and will be less numerous. If fish are less numerous, marine mammals and birds will have less to eat too.
The news may not be all bad. Global warming is caused by increased levels of carbon dioxide in the atmosphere. Many plants, including crops such as cotton, soybeans, wheat, and rice, can benefit from the increase in CO2. They can absorb the CO2 and yield more at harvest time as a result. On the other hand, in warmer weather crops may also be more at risk from insect pests and from severe storms or droughts.
Unanswered Questions
Scientists have little doubt that Earth’s climate is changing. Unfortunately, it is impossible to predict exactly how any particular ecosystem will be affected by global warming. However, biologists and climatologists are collecting data about processes including solar radiation, precipitation, evaporation, the transfer of heat energy by winds and by ocean currents, and the ways in which plants affect climate. Then, by using computer models that interpret this information, they can begin to answer questions about how global warming will affect Earth.
- Does global warming cause the number of tropical storms and hurricanes to increase?
- Could global warming alter certain ocean currents, changing Earth’s temperatures further?
- How quickly might the polar ice caps melt?
- How have global climate changes affected Earth's ecosystems in the past?
UPDATES: Straight from the Headlines
- States Enact Regulations to Cut Greenhouse Emissions
- Global Warming Research: Understanding the Situation
- Researchers Work to Combat Climate Change
- Polar Bears Listed as "Threatened" Under the Endangered Species Act
- Climate Change May Threaten Australia's Kangaroo Populations
- Charging to Pollute
- Increased Global Temperatures Impact Seed Dispersal in Northern Forests
Technology
Deep Sea Sediment Coring
Analyzing ocean floor sediments can provide scientists with data about how plants and animals were affected during past climate changes. The process of collecting deep sea sediments is expensive and time-consuming, but the results of this research give scientists a look at what life in the oceans was like millions of years ago.
To study these ancient organisms, scientists need sediment samples that are hundreds of meters long. To obtain these, they must use drills similar to the drills used by the oil and gas industry. Taking these samples requires many hours and can be dangerous if the seas are rough or full of ice. Once scientists have obtained the cores, they first split the core in half lengthwise. One half is sampled for fossils of ancient organisms. This is the "working half." The other half, the “archive half,” is saved and stored away so that future scientists who may develop other questions can have access to this difficult-to-obtain material.
By carefully dissecting the working half of the sample, scientists discover microscopic fossils of marine animals. Scientists know that these ancient animals were very sensitive to slight changes in temperature and chemistry. These microfossils can tell scientists how Earth’s climate has changed over millions of years.
Careers
Oceanographer in Action
Ruth Curry
Title: Oceanographer, Woods Hole Oceanographic Institution
Education: B.S., Geology, Brown University
For Ruth Curry, spending time on the ocean waves has nothing to do with surfing or vacationing. She spends her time studying the ocean currents that affect our lives each day. Ruth Curry is an oceanographer at the Woods Hole Oceanographic Institute, an organization of scientists who research and study how the ocean affects the global environment.
Curry's research focuses on the North Atlantic circulation and the currents that carry warm waters from tropical regions northward. As these warm waters reach higher latitudes, they release heat that warms the air above them and warms the climate of western Europe. As warm water cools, its density increases and it sinks to the bottom of the ocean. There it begins a southward journey back to the tropics. This conveyor belt of water plays an important role in maintaining Earth’s climate. Normally, the salinity, or saltiness, of ocean water stays about the same. But changes in global temperatures are melting large sheets of ice in Greenland, which is introducing large amounts of fresh water into the ocean. This fresh water is diluting the ocean water, making it less salty. A decrease in salinity makes ocean waters less dense and prevents them from sinking to the bottom of the ocean. Eventually, the melting of ice sheets in Greenland could cause the North Atlantic currents to slow and eventually stop, leading to dramatic changes in the Northern Hemisphere’s climate.
Comments
Comment from: kyle
August 31, 2009 08:04 AM [#]
its sad to hear bout the dying polar bears
Comment from: kyle
August 31, 2009 08:06 AM [#]
im with you on the articles
Comment from: dean
September 14, 2009 12:57 PM [#]
i believe in this article beacase where i live there weird climate occurance so thanks for the information
Comment from: Smart Kid
September 18, 2009 11:19 AM [#]
If the polar bear were to go extinct, they wouldnt eat any more sea lions. then the sea lions would eat all their food up and then they would die. And then the other organisms that eat Sea lions would die and the thing that they eat would eat all their food and then they would die.
Comment from: Jayfeather
September 22, 2009 07:08 PM [#]
poor animals. but that's the way mother nature planned....
Comment from: Jamie
September 24, 2009 04:14 PM [#]
I think that humans can prevent global warming. Some of this serious climate change may be natural, but most of it is reversable, or was reversable.
Comment from: Inez
October 28, 2009 03:40 PM [#]
It doesn't make sense to say that it's okay to let things stay the way they are now. If you really believed that, you wouldn't go to the doctor, people wouldn't avoid wars, and who would bother giving babies their vaccinations? So why don't you take a look at the world outside yourself?
Comment from: D Noll [MMHS Per. 4]
November 7, 2009 02:11 PM [#]
Global Warming... "What can we do to prevent it... the polar bears are going to go extinct... Global Warming is bad I wish I new how to stop it..."
Millions of people ask there self this question when they know the answer; they just don't want to do anything about it. But, that is when people like Ruth Curry come into help. The problem is there is not enough Ruth Currys out there to make up for all of the inconsiderate small minded individuals and groups out there...
We did not 100% cause global warming, but we definitely played our part in it. The weather is forever going to change and so are humans. Society is going to change and if we accommodate with the planet we could postpone these awful situations. We do this so we can say we did everything we could think of to "save the polar bears"
Comment from: KCole
November 8, 2009 07:46 PM [#]
This article was very intresting to me. In my belief I think that if we don't do something about global warming it will harm us in the future.All the goverment does is post signs about global warming but i think they should act fast and find out ways to prevent global warming.
Comment from: FDe Leon(MMHS P2)
November 16, 2009 05:51 PM [#]
I think that everyone should read this article and see the effect we are doing to this planet. Polar bears may soon be extinct if we do not do our part and help to stop global warming instead of standing or sitting around saying what we should do and not doing anything.
Comment from: Rgomez MMHS P6
November 17, 2009 08:34 AM [#]
If this continues it won't just be the polar bears
Comment from: DGuizar (MMHS P2)
November 18, 2009 04:24 PM [#]
sad artile. Is there a way to reverse it?
Comment from: JOmoto (MMHS) P7
November 22, 2009 10:22 PM [#]
Very interesting
Comment from: VGonzalez(MMHS P5)
November 23, 2009 02:28 PM [#]
This article was very interesting. I think that it is sad that some people are not doing anything about global warming. People should start doing something about global warming, because if we dont do anthing now, it will harm us in the future.
Comment from: DTrenco (MMHS P1)
November 23, 2009 08:11 PM [#]
if we stopped polluting our Earth we wouldnt have global warming.
Comment from: MVargas (MMHS P6)
November 27, 2009 07:00 PM [#]
People need to start getting more proactive about helping the environment or else more living things will start to become extinct. Sooner than later we will start to run out of recourses and more and more medical problems will occur
Comment from: AGallo (MMHS P5)
November 29, 2009 02:22 PM [#]
I think that the rate that global warming is increasing is scary and that people should become more active in changing things we do in order to prevent more of the harmful effects that we will be experiencing if we don't .
Comment from: VPinell [MMHS P4]
November 30, 2009 07:26 PM [#]
it is sad that the polar bears might get extinct because of us not being more "green" and caring more about the world we live in. i hope that the future gets better so that my kids will be able to see a live polar bear.
Comment from: JRobidoux (MMHS P5)
December 5, 2009 02:11 PM [#]
I was amazed at just how serious global warming was. this article was very enlightening and informational for me.
Comment from: EMay(MMHS P5)
December 6, 2009 05:57 PM [#]
This is really sad that these animals are going extinct because they have no say and cant change things.
Lets hope that this really doesnt happen
Comment from: BLara(MMHS P6)
December 7, 2009 09:36 PM [#]
I believe that we are the cause of global warming and the animals are the ones who have to suffer for our mistake. Even though the temperature will only raise to 0.4ºF each decade, it really adds up. What will the ice look like in 10,20,30 years from now? I know it won't be what we want to end up happening, but if we don't change ours ways now, who knows what will happen. Not only are the polar bears at the poles are being effected, but animals as small as microscopic organisms. We are the main cause of this only because of the need of production we have. Cotton and farming plants produce lots and lots of CO2 and it is greatly effecting the environment. Maybe one day, our factories and plants can use eco-friendly materials to still get the job done, and save our plant and everything on it.
Comment from: KBeckingham (MMHS P5)
December 9, 2009 09:28 PM [#]
This article was very informative about global warming and how it's affecting our planet.This is a serious problem.
Comment from: IRobinson(MMHS P3)
December 11, 2009 07:43 AM [#]
wowo who new a little hottness chould do this :(
Comment from: ::::"miguel"::::::
December 18, 2009 10:37 AM [#]
wow hottness can make animals go extinct
Comment from: arely
January 29, 2010 08:43 AM [#]
i say we should stop global warming its dangerous for animals.:/