One of the most striking ongoing changes in the Arctic is the rapid melting of sea ice. Some climate models predict that, sometime during the first half of the 21st century, summer sea ice will vanish from the Arctic Ocean. An absence of summer ice would amplify the existing warming trend in Arctic tundra regions as well as in regions beyond the tundra, because sea ice reflects sunlight much more readily than the open ocean and, thus, has a cooling effect on the atmosphere. In addition, research indicates that the retreat of sea ice would enhance the productivity of tundra vegetation, and the resulting buildup of plant biomass might lead to more extreme events such as large tundra fires. Finally, an ice-free Arctic Ocean would improve access to high northern latitudes for recreational and industrial activities; this would likely place additional stress on tundra plants and animals as well as compromise the resilience of the tundra ecosystem itself. In alpine tundras too, climate warming could encourage more human activity and increase damage to plant and animal populations there.
The fate of permafrost in a warmer world is a particularly important issue. Together, tundra and taiga account for approximately one-third of global carbon storage in soil, and a large portion of this carbon is tied up in permafrost in the form of dead organic matter. Some of this organic matter has been preserved for many thousands of years, not because it is inherently difficult to break down but because the land has remained frozen. Thawing of the permafrost would expose the organic material to microbial decomposition, which would release carbon into the atmosphere in the form of CO2 and methane (CH4). Rates of microbial decomposition are much lower under anaerobic conditions, which release CH4, than under aerobic conditions, which produce CO2; however, CH4 has roughly 25 times the greenhouse warming potential of CO2. The Arctic has been a net sink (or repository) of atmospheric CO2 since the end of the last ice age. At the same time, however, the region has been a net source of atmospheric CH4, primarily because of the abundance of wetlands in the region.
The study of geography helps educate people on preserving the climate.
For example , we learn about how deforestation affects the quality of the water, and leads to loosened soil. We learn that we need plants to purify our water.
Deforestation also means lesser plants to give out oxygen and as a result increase global warming, creating extreme changes to climates. This can create droughts and famine and affect food production for the community.
Fossils of the plant Glossopteris have been found on South America, Africa, India, Antarctica, and Australia. The only way these fossils can be found on continents that are separated by oceans is if the continents were once together (connected).
Answer:
Quaternary period
Explanation:
Throughout the <u>quaternary</u> period, which began about 2.6 million years ago and extends to the present, ice sheets formed, advanced over broad areas, and then wasted away.
The quaternary period is a geological time period that began 2.6 million years ago and encompass the present time. This time period is divided into two; the Pleistocene Epoch, which lasted from approximately 2 million years ago to about 12,000 years ago, and the Holocene Epoch, which began about 12,000 years ago. This period is referred to as the ice age due to formation of ice sheets during this period, some of the ice sheets became glaciers. These accumulated ice sheet wasted away when the earths atmospheric temperature increased.
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Answer: It is the result of a mixture of radiation from many independent sources, such as stars and galaxies.</h2>
Microwave background radiation is a form of electromagnetic radiation that <u>is present in the whole universe</u> and completely fills it. It is the leftover radiation from the big bang
.
Its frequency belongs to the microwaves range and is one of the main demonstrations of the of the Big Bang theory model.
It is important to note the Big Bang occurred 400,000 years before the events related to the microwave cosmic radiation, this means the Big Bang occurred first.