Final: The Effects of Global Warming on the Frog Species of Monteverde Cloud Forest

This discussion topic submitted by Ellen Kretchmar ( at 10:28 am on 7/1/99. Additions were last made on Wednesday, May 2, 2001.

Final Discussion Topic

Topic in General: Global Warming

In specific: The Effects of Global Warming on the Frog Species of Monteverde Cloud Forest

I. Global Warming
A. What is Global Warming?
B. Greenhouse Effect
C. Major Greenhouse Gases
1. Carbon Dioxide
2. Chlorofluorocarbons
3. Methane
4. Nitrous Oxide
5. Perfluorocarbons
D. Rise in Atmospheric Levels of Greenhouse Gases
1. Causes
2. Effects
3. Diagram
E. Is Global Warming a Serious Threat?
II. Frog Species Extinction Linked to Global Warming
A. Alan Pounds Says Sound Alarm
B. Reported in the Journal Nature April 15, 1999
C. Decline Coincided with Reduced Moisture Level
D. Serves as Evidence that Global Warming Affects Wildlife
E. Climate Shift Caused Base of Cloud Bank to Lift
1. Mist/Condensation Decrease
2. Dry Season Becomes Longer and Warmer
3. Birds from Lower Drier Elevations Move Upward
4. Amphibians of Higher Elevations Nowhere to Move Upward
F. Golden Toad Disappearance and Other Frog Extinction Indirectly Linked to Climate Shift

In general my topic is about global warming and I want to relate it specifically to its effect on the frog species of Monteverde Cloud Forest Reserve in Costa Rica. What is global warming? It is the natural or human-induced increase in the average global temperature near the earth's surface (Miller 1996). It is the Greenhouse Effect that causes global warming. The Greenhouse Effect is where certain gases in the atmosphere trap heat in the

The major Greenhouse gases are carbon dioxide, chlorofluorocarbons, methane, nitrous oxide, ozone, and water vapor. The amount of heat trapped depends on the concentration of the Greenhouse gases and how long they stay up in the troposphere. As for C02, it constitutes 50% of the Greenhouse gas produced by
humans and 75% of that is produced by the burning of coal. A carbon dioxide molecule stays in the troposphere for 50-200 years. As for CFCs, the source of this Greenhouse gas is leaking air conditions, refrigerators, and aerosols. They are the most potent molecules in terms of the amount of heat they trap; they trap 7,000 times as much as carbon dioxide. As for CH4, these molecules are produced when anaerobic bacteria break down organic matter. Areas where is done include swamps, wetlands, landfills, intestinal tract of cows. One molecule of methane traps 25 times as much heat as one molecule of carbon dioxide and it stays in the troposphere only 9-15 years. As for N2O, the main source of this gas is fertilizer, it is 230 times more potent than CO2, and stays around for 120 years. A newly reported Greenhouse gas is perfluorocarbons (PFCs). This gas is produced primarily from aluminum production and it stays in the troposphere for a very long time anywhere from 2,000-5,000 years.

It has been reported that measured atmospheric levels of certain Greenhouse gases have risen substantially in recent decades. The increased levels have be noticed since 1958 and attributed to human activities. These activities include fossil fuel burning, agriculture, and deforestation. Remember though,
global warming is caused by human contribution AND by nature.

Some of the effects of global warming are caused by simple science. The northern hemisphere warms more and faster because it does not have as much heat-absorbing ocean as its southern counterpart. The rate of water evaporation will increase, thereby increasing the average global temperature. With a
warmer climate, global sea levels will rise because water molecules expand when heated. Also, warming will cause ice sheets and caps to melt eventually, however it will take hundreds of years.

According to Alan Pounds, it's time to sound the alarm about loss of biodiversity due to global warming. Human activities and natural cause increases in Greenhouse gases, Greenhouse gases cause global warming, then
global warming causes climate shifts, and climate shifts cause droughts, floods, rises in sea levels, and loss of biodiversity including the extinction of twenty frog species in Monteverde Cloud Forest Reserve. It was reported in
the Journal, Nature that the extinction of the indigenous Golden Toad coincided with reduced moisture levels on the area. It is time to sound the alarm because this is supporting evidence that global warming is a serious threat
because it is affecting wildlife. As we saw, the cloud forest is home to many plant and animal species and most of this species are dependent on its moisture level. It is of these moist-dependent species that researchers have noticed
population size reductions. Researchers have also noticed an upward migration of many bird species who are adapted to the drier conditions which also supports the fact of a drop in moisture level. This drop is caused by the
climate shift that caused the base of the cloud bank to lift. As the cloud recedes up the mountain, the mist and condensation is decreased. Also, the dry season becomes warmer and longer. The birds move up from lower elevations to higher but now drier elevations, however, the amphibians have nowhere to go.
This example, the Golden Toad extinction, is the first species attributed to the modern climate change according to the Declining Amphibian Population Task Force. To these researchers and others, it is time to sound the alarm about global warming's effects on biodiversity.

Course Packet. A Crisis in the Making: Responses of Amazonian Forests to land use and

climate change
Neotropical Companion
Miller, The Living Environment
Washington Post

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