Making real science accessible and interesting for all people.
Showing posts with label climate change. Show all posts
Showing posts with label climate change. Show all posts
Friday, November 30, 2012
Global Climate Change: Thawing of the Arctic Tundra
The above is a great short video about the effects of the warming planet on Arctic tundra. Tundra by definition is ground that is permanently in a frozen state. During the short and few summer months, tundra only thaws on the surface. Deeper down however, the ground remains frozen year round. This only allows for small shallow rooted plants to grow and prevents larger plants such as trees from ever taking root into the frozen ground. The constantly frozen ground also does not allow plant materials to decay once they die. Dead plant materials simply die and other plants grow on top of them. This causes a thick accumulation of dead, un-decayed plant materials to pile-up, forming peat. The great expansiveness of peat in Arctic tundra is a gigantic holding place for a huge amount of carbon dioxide. The carbon dioxide simply remains locked up in the peat because of the cold and frozen conditions. Recent warming of tundra peat however has caused some thawing and therefore allowing decay to take place in this peat. As the decay takes place, carbon dioxide that was held in the peat is released into the atmosphere contributing to increased global temperatures. Anyway, check out the above video for a short look on a scientific experiment and some of the potential effects of a warming climate.
Monday, November 26, 2012
Huricane, Superstorm, Frankenstorm Sandy... What Made This Storm So Bad
Watch Inside the Megastorm on PBS. See more from NOVA.
The science and story behind the development of Superstorm Sandy is fascinating. The above video does a great job of explaining the development of this storm and how so many different weather elements came together to make this storm so bad. The combination of a hurricane, absence of the Bermuda High, higher than usual ocean temperatures, a Nor'eastern storm, high pressure of the coast of Greenland, an adjusted jet stream, and the storm making landfall at the full moon high tide all came together to make this frankenstorm. A hurricane or nor'eastern storm are bad enough, but the combination of these two along with everything else made this storm devastating. Though Sandy was quite a dramatic weather event, the above video gives a great education on weather in general. The big question now is, will superstorms like Sandy become more common in the future? In the next 100 years temperatures are expected to warm by about four degrees which would likely increase the number and intensity of storms throughout the world. Are storms like these a preview of what is to come in the future?
Friday, November 16, 2012
Joshua Trees, Ice Age Sloths, Extinction, and Climate Change Today
With the end of the Ice Age, the giant Shasta ground sloth became extinct in our American Southwest deserts. This extinction happened as a result of the warming of the continent and invasion of humans into the land 13,000 years ago. Today, the sloth is long gone, but the consequences of its extinction are still being seen to this day. The Shasta ground sloth was intimately intertwined with every organism they ate, use, or associate with. Of course, all organisms that inhabit this earth are intertwined in the same way with all the organisms they eat, use, and associate with both directly and indirectly. This can be extended to show that all organisms are in one way or another connected. If one organism is removed from an ecosystem, such as the ground sloth, every other part is affected and must adjust their life accordingly.
Unfortunately, not every organism is able to adjust to every change in an environment. Such was the case of the Shasta ground sloth. As the climate warmed, plants that inhabited the Southwestern deserts changed, changing the sloths food sources. As food sources changed, the sloth could not adjust and as a result became extinct. As a result, the plants and animals affected both directly and indirectly by the sloth had to adjust to "life after the sloth". For example, the Joshua Tree was a major part of the sloths diet. At first it may seem that extinction of something that is eating you might be a good thing. At first, I could guess, the Joshua tree might have benefited greatly by the absence of a giant animal consuming it. Long term however, the Joshua tree suffered greatly and continues to suffer to this day. As the sloth ate the Joshua tree, of course this injured the plant. However, as the sloth ate, it also consumed the Joshua tree seed which would pass all the way through the sloths digestive tract without being damaged. Once passing though the sloths digestive tract the seed would find itself in a moist pile of fertilizer, which is an extremely ideal location to find yourself if you are a desert seed in desperate need of moisture and nutrients.
With this association of the sloth and Joshua tree, the sloth benefited with food by eating the tree. The
Joshua tree made a trade-off though, being damaged by the sloth as it was eaten, but benefiting from the sloth into the next generation. The sloth aided the success of the Joshua Tree by likely aiding germination and by carrying the seeds to new locations up to ten miles away. After the extinction, and up to the present day, only desert squirrels and packrats move Joshua tree seeds today, and only at a pace of about six feed per year. As a result, the Joshua tree cannot adjust its range anywhere near as quickly as it could before and its range has been shrinking for over 10,000 years now. How do we know all this? Scientists in the Southwest have examined caves where sloth dung which tells us what the sloth ate. Ancient packrat middens also have been examined which tell us where the Joshua tree was and when over the last 10,000 plus years.
With the ability to only change their range six feet per year, the Joshua trees range will continue to shrink in coming decades. Currently, the climate is warming far to fast for the Joshua tree to keep pace. This does not mean however the Joshua tree will go extinct. It will be able to survive in cooler high elevation locations. As the range of the Joshua tree is reduced however, organisms dependent on it will have to adjust. For example, many species of rodents are dependent on moisture from the tree during times of drought. These organisms access water from the tree simply by chewing through the bark to access water. With the trees gone however, there will be far less water available to support rodents. And so we see the continued consequence of the extinction of the sloth.
Joshua tree made a trade-off though, being damaged by the sloth as it was eaten, but benefiting from the sloth into the next generation. The sloth aided the success of the Joshua Tree by likely aiding germination and by carrying the seeds to new locations up to ten miles away. After the extinction, and up to the present day, only desert squirrels and packrats move Joshua tree seeds today, and only at a pace of about six feed per year. As a result, the Joshua tree cannot adjust its range anywhere near as quickly as it could before and its range has been shrinking for over 10,000 years now. How do we know all this? Scientists in the Southwest have examined caves where sloth dung which tells us what the sloth ate. Ancient packrat middens also have been examined which tell us where the Joshua tree was and when over the last 10,000 plus years.
With the ability to only change their range six feet per year, the Joshua trees range will continue to shrink in coming decades. Currently, the climate is warming far to fast for the Joshua tree to keep pace. This does not mean however the Joshua tree will go extinct. It will be able to survive in cooler high elevation locations. As the range of the Joshua tree is reduced however, organisms dependent on it will have to adjust. For example, many species of rodents are dependent on moisture from the tree during times of drought. These organisms access water from the tree simply by chewing through the bark to access water. With the trees gone however, there will be far less water available to support rodents. And so we see the continued consequence of the extinction of the sloth.
Monday, September 24, 2012
Bringing back the Wooly Mammoth
The last known population of Wooly Mammoths went extinct about 4,000 years ago. The last population existed on Wrangel Island off the coast of Siberia. Wooly Mammoths were extremely elephant like in both size and shape. The big differences though between the two lies in their adaptation to climate. Modern day elephants are adapted to the tropics. Wooly Mammoths had fur similar to yaks and a thick layer of fat to help hold in heat. Mammoths also had smaller ears which helped them hold heat in better. These adaptations are of course why the mammoth lived in the icy tundra and thrived during the ice age. As the world warmed, bringing the ice age to an end, suitable habitat and areas of food shrunk significantly for the mammoth. The warming climate along with increased human hunting pressure at the end of the ice age led to the extinction of this huge mammal.
Even though the mammoth has been extinct for 4,000 years now, scientists are working to clone one back to life again. The process is simple in theory. Scientists must first find a living mammoth cell and extract the nucleus. The nucleus of a modern day elephant embryo must be removed and replaced with the mammoth nucleus. Then, this embryo must be impregnated into an elephant mother. If the embryo survives, a baby mammoth will be born to the mother elephant. All of these processes are well known and have been successfully carried out, but never for wooly mammoths. In practice however, this process appears nearly impossible. The first step of finding living mammoth cells is what makes this so difficult. But once living cells are found, the rest of the process would be relatively simple.
The preference of mammoths for icy cold habitats is what makes this entire process possible in theory. As mammoths died in the frozen tundra, there is the very likely possibility their bodies would have frozen very quickly, thus preserving living cells in a frozen state. Indeed, many frozen specimens of ancient mammoths have been found. Not a single living cell in these frozen specimens has been found though and the probability of a cell surviving thousands of years even in a frozen state isn't very high. It is still possible though. And just the fact that it is possible makes at least a few people want to try. Just think how awesome it would be to go visit a living wooly mammoth at the zoo. Or see a wooly mammoth performance when the circus comes to town. OK, that's sort of silly but just think...
Monday, September 17, 2012
Ocean Acidification
Ocean acidification is becoming a serious issue today. Within the next hundred years it will become extremely serious. Since the industrial revolution the oceans have been absorbing huge amounts of carbon dioxide due to the burning of fossil fuels. As the oceans absorb this carbon dioxide it is converted into carbonic acid. Oceans have already dropped 0.1 in pH and are predicted to drop another 0.3 to 0.5 in pH within the next 100 years. These drops in pH might not seem like much but in reality are over a 100 percent increase in acidity. This increase will have extreme consequences for shell forming organisms. As acidity increases, the calcium in shells increasingly dissolve. This can kill the organism or cause it to work harder to develop its shell. Corral reef also will have increasingly difficult times forming as acidity increases. In-fact, many people predict all corral reefs will be gone by the year 2050, which means a mass extinction of organisms that are completely dependent on corrals. As shell bearing organisms disappear, organisms higher up the food chain also will disappear along with there food sources. No one really know what exactly is going to happen, but everyone agrees it will not be good. Fortunately, the solution to this problem is within reach. To prevent continued acidification we must stop the mass burning of fossil fuels and switch to sustainable energy sources such as wind and solar. Only with this switch can we decrease the increase in carbon dioxide and therefore stop global warming as well as ocean acidification. Below is a documentary that aired on Discovery Planet Green that does an excellent job covering this topic.
Friday, July 6, 2012
Where Did All the Saber-Tooth Tigers Go?
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Actual picture I took of a Saber Tooth Tiger. I found him right after I had a nice conversation with Bigfoot. OK, just kidding. But really, where did all the Saber Tooth Cats go??? |
The most widely known explanation for the extinction of large mammals at the end of the Ice Age is over hunting by humans who recently colonized the continent. This is a very simple explanation, humans, new to the continent simply hunted the large mammals until there where no more. The problem with this hypothesis is that the human population was probably not dense enough to exert such a huge hunting pressure.
A second explanation is the climate change at the end of the Ice Age. Warming caused a change in the available food for all animals. This caused starvation of large herbivorous mammals, therefore causing the predators to starve also.
A third explanation is that when humans invaded the continent, they altered the ecosystem so that it could no longer support many large mammals. Of course hunting played a role in this, but also as humans consumed plants, and used fire to alter the ecosystem. As humans ate certain plants, animals had to change their food sources. As humans burned areas with fire, say changing a forest into a grassland, only certain animals could survive. Basically, humans altered the ecosystem in ways that changed food chains, causing some animals to die off and others to thrive.
A fourth explanation is the most complex. It is that all three of the above played a role in the extinction of large Ice Age mammals. Through a combination of a warming climate changing food sources for animals, hunting by humans, and human alteration of ecosystems by use of fire and harvesting of plants and animals, large mammals went extinct. This seems to be the latest consensus of the scientific community. Different species of animals would have gone extinct as a result of different factors. Some may have been hunted to extinction, others died as their food source changed, and others died as their ecosystem changed.
All this has huge implications for our world today. Today again we are going though a change in the climate. Plants and animals are having to adjust what they eat and where they live as the weather warms. Humans also are changing the landscape in very drastic ways, also causing animals and plants to change where they live. Basically, those that are able to survive and adapt to these changes will survive. Those that can't will die off.
Oh-ya, there is another explanation for the Saber-Tooth Tiger that a few people support. That is, that the Saber-Tooth Tiger is still living today, probably hidden away in some remote forest cave as a pet of Bigfoot or the Lock ness Monster. Hmmm...
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A man about to be eaten by a Saber Tooth Cat. The man has no idea what's coming. |
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