Current Climate Change and Mitigation - Research Paper Example

Climate change is one of the greatest threats to modern civilization. Earth is currently experiencing a rapid increase in mean temperature. The global scope of this phenomenon makes it particularly challenging because efforts to address the problem require cooperation between many different nations and international corporations. Add to this the disagreements over the veracity of the problem and the mechanisms causing our planet to warm, and what you will find is a very dangerous situation with no easy remedies. Earth’s climate is a changeable climate. We know through studying dendrochronology, ice core samples, mud core samples and historical records that the earth has gone through many cyclical changes in climate over the millennia. As little as 1000 years ago, the earth experienced a period of rapid warming known as the Medieval Warming Period. Northern locations, such as the southern regions of Greenland became inhabitable and were colonized by Viking settlers. A mere 200 years ago saw the northern hemisphere experience a climate anomaly known as the Little Ice Age. European glacial ice advanced down mountain sides, growing seasons shortened and crops failed. What caused these most recent episodes of climate change? That question is an important one because its answer is at the heart of the current debate surrounding the veracity of our current heating. Many complex systems help to regulate earth’s temperature. The circulation of warm waters from equator towards pole and cold water from cold to warm helps to evenly distribute heat in the northern and southern hemispheres. Changes in this thermohaline circulation have been linked to periods of cooling on earth. The amount of aerosols emitted from volcanic activity is also a factor that determines world climate. Other determinants involve the changing degree of axial tilt of the earth and the variable distance between the earth and the sun caused by an ever-changing (albeit slowly) orbit around the sun. None of these systems appear to be under the control of human beings. So when they cause climate change, either gradually or rapidly, it is beyond human control. Most scientists today do not feel that these natural systems are the cause of our most recent warming, however. They point to the fact that the earth is heating very rapidly during the past few decades. Even during climate anomalies like the Little Ice Age and the Medieval Warming Period, the climate did not change as rapidly as it is changing now. On the other hand, some scientists are finding that the climate has the ability to change rapidly. It is as if various feedback cycles work to keep climate stable for as long as possible until a certain threshold is crossed (Alley, 2003). Once that threshold is breached, then the world’s climate makes a sudden change, either by warming or cooling. This does not suggest that our rapid heating of the past few decades is not something to be worried about. The study does suggest that it is a cause of special concern because much of our heating may be manmade. This is in addition to natural feedbacks that may already be operating, sending us towards an abrupt climatic shift. Many scientists agree that our current accelerated warming is the result of gasses being emitted into the atmosphere by human activity. These gasses are known as greenhouse gasses because they allow the heat of the sun to enter the earth’s atmosphere but then trap it before it can reradiate out into space. Under balanced conditions, greenhouse gasses keep the climate stable, but when they build-up warming occurs. The two most common greenhouse gasses are carbon dioxide and methane. Millions of tons of these gasses are being emitted each year from human activities such as burning fossil fuels and agricultural practices. Most scientists feel that if we cease emitting carbon dioxide and methane at the current rates and seek alternatives to burning fossil fuels, we may be able to slow the rate of warming. So what is the big deal about a warmer climate anyway? The earth has been through this before, even if it wasn’t caused by humans the other times. Is climate change really a threat to anything other than a few mountain glaciers and some species of animals that depend on them? The answer is clear from science. Climate change, especially rapid climate change of the type that we are currently experiencing is very damaging to many ecosystems on the earth. These are the same ecosystems that directly support human life or support the economic activities that provide humans with all of the modern conveniences and luxuries we enjoy today. Several important ecosystems will be greatly affected by a rapidly warming planet. One massive ecosystem is the boreal forest found through much of the northern hemisphere north of 45o latitude. This ecosystem is very fragile. It provides more atmospheric oxygen than all of the rainforests on earth combined, but grows very slowly due to the cold climate. As predicted by some climate models, the boreal forest will dry out in a warming climate. This will make it more susceptible to forest fires that will destroy the oxygen producing trees and dump even more carbon dioxide into the atmosphere. This will create a devastating positive feedback for continued global warming. Another ecosystem to be greatly affected by the warming climate is the ice sheet climates near the poles. Recent melting events in the northern hemisphere have some scientists predicting that all of the northern ice sheets will melt each year during summer within the next thirty years. Many species of animals are dependant on the ice to sustain their established procedures for mating, birthing and feeding. Of special interest is the effect the melting northern ice will have on established marine food webs in the region. The melting of ice sheets in the seas surrounding Antarctica has potential to disrupt the migration of whales and penguins, as well as creating hazards for human economic activities such as shipping in the southern oceans. Aside from the polar marine ecosystems threatened by melting ice, another marine ecosystem is under tremendous stress caused by global warming. Within the last decade, nearly 1/3 of all coral species have been placed in jeopardy of irreversible harm (Kent E Carpenter, 2008). These endangered coral reefs are spread throughout the world, but are concentrated mostly in warm tropical waters. Of greatest concern are corals in the Caribbean Sea and the waters surrounding the islands of Indonesia. While they are all threatened for a variety of reasons, their survival is important for marine ecosystems and human populations. Coral reefs are often referred to as the rainforests of the ocean (Normille, Warmer waters more deadly to coral reefs than pollution, 2007). This similarity is most accurate when one considers the variety of species that inhabit coral reefs. Incredible symbiotic relationships exist on healthy reef systems. This variety alone is enough to engender the love of humans for these reefs. But in addition to the visual splendor of a coral reef, ecologically important services are being provided by the reef such as sequestering dissolved carbon dioxide, providing safety for coastal communities of humans and offering economic opportunities in some of the poorest parts of the world. The threats to coral reefs by a warming climate are many. Changes in storm patterns, water chemistry and ocean temperature all affect the health of coral reefs. An understanding of what creates a coral reef is important to know why these changes affect the health of the reef. Coral reefs are formed by coral polyps. This is an animal much like an anemone. Within each polyp is the ability to absorb dissolved carbon dioxide that is used to crease a sort of exoskeleton that protects the polyp. In addition to this, each polyp has symbiotic algae that dwell under its skin. These algae must be near the surface of the water in order to use photosynthesis to produce nutrients that keep the algae and the coral polyp alive. This cooperation causes the polyp to grow year after year, discarding the old carboniferous skeleton and growing a new one. The calcium carbonate skeletons glob together to give the reef its distinctive shape and structure. This structure creates homes and hiding places for many marine species. If the coral polyp dies, the calcium carbonate reef remains behind, but it looses the color given to it by the algae and the polyps. The reef erodes and becomes “bleached”, a term used to describe a dead reef. Beyond ecology, coral reefs are important to humans economically. Nearly 30 billion dollars of fish are harvested from coral reefs each year (Stone, 2007). In a very real way, coral reefs are important to millions of humans because their health and existence determines the difference between a full stomach and hunger, between unemployment and employment. Using this resource in a sustainable way is vital for these coastal communities. What are the real human threats to coral reefs? Until recently the biggest threats were from overfishing and depleting stocks of symbiotic fish that would upset the ecological balance of the coral reef. Another threat was from nutrient pollution from chemical fertilizers. Increased nitrogen levels from agricultural runoff favored the growth of seaweeds that crowd out the symbiotic algae, thus killing the coral polyp. But these are no longer the greatest threats to coral reefs. Scientists have identified the greatest threat to coral reefs are coral bleaching caused by increased water temperatures (T.P. Hughes, 2003). In general, a 1oC increase above the normal maximum temperature is enough to cause coral polyps to expel their symbiotic algae. Due to the lack of nutrients the algae provide, the coral polyps may die. It is important to note that corals in warm areas, like the seas off of the Arabian Peninsula are able to exist at a full 10oC warmer than corals in the North Atlantic Ocean. What matters is the difference in the normal temperature for that spot. Some corals also do not bleach as quickly as others. This has some scientists hoping that perhaps coral polyps will be able to adapt to the changing water temperatures. The problem with this lies with the reefs apparently slow ability to adapt to change. Waters are warming so rapidly, the ability to adapt doesn’t look like a good defense for the reefs. A look at the geologic record reveals that the range of a reef species can change and adapt to climate changes. The problem with using the geologic record as a gauge stems from the fact that people have placed another layer of stress on reefs that can’t be accounted for in the geologic record. Another threat to the structure of coral reefs caused by global warming concerns changes in water chemistry. More carbon dioxide in the oceans of the world means that it is more difficult for coral polyps to form their calcium carbonate support structures. It seems that the opposite would be true, that more carbon dioxide would means more for the corals to process into exoskeletons. Unfortunately, the excess carbon dioxide forms carbonic acid and actually begins to erode the existing reef. Evidence of this is found in the fossil record, where during the late Triassic period there were almost no coral reefs formed. Scientists believe that this is because the amount of atmospheric carbon during this time was about five times greater than it is now (O. Hoegh-Guldberg, 2007). The increased carbon dioxide may also damage the reefs by making them more brittle and easer to damage. This type of damage is now showing up in even the best managed coral reefs. The Great Barrier Reef has been protected since the 1970’s, yet it is still being weakened by changes in water chemistry. One study suggests that the decrease in calcium carbonate accretion is the greatest seen in the past 400 years (Death, 2009). A final threat to the health of reefs is biological in nature. Coral reefs, like other living organisms, have natural defenses against biological invaders. Like the human immune system, a coral reef when in balance can handle invasive organisms that would cause the reef harm. But when weakened, the reef can not fight off or adapt to invasive species. The world’s weakened reefs are currently under biological attack (Ricciardi, 2006). Invasive corals are now showing up where they never have before. These organisms are just one more disruption that works to weaken the overall health of the reef biome. A variety of methods to mitigate the deterioration of coral reefs are being discussed. They run the gamut of human endeavor. Most scientists see the wisdom in learning as much as possible about what a healthy reef system looks like so it can be replicated. Approaches to rehabilitation and rejuvenation of reefs vary according to the ingenuity of the scientists implementing their ideas. Technology as a tool is also being enlisted to gather relevant data to monitor improvement or continued deterioration of coral reefs. Technology is being viewed as a key component of studying and conserving coral reefs. Remote sensing, in conjunction with Geographic Information Systems (GIS) allows scientists to gather data on bleaching incidents, coral growth and storm damage (Vanderstraete, 2004). This technology provides a constant stream of data that can be used to make management decisions, especially those that deal with coastal development near coral reefs. A compilation of this data has been consolidated into a world map that shows areas of the globe that are most threatening to coral reefs (Halpern, 2008). These tools will be useful in tracking the effectiveness of each attempted process used to mitigate damage to the coral reefs of the world. Some possible solutions that are being contemplated to mitigate damage were once thought of as primary causes of degradation. Tourism is one of these possible solutions. In the Florida Keys alone, tourism of the local reefs is a 1.6 billion dollar industry (J.M. Pandolfi, 2005). Economic incentives for preservation may grow as the tourism industry recognizes the importance of clean, healthy reefs. Enlisting tourism companies to educate their customers about the need for healthy coral reefs would also be a way to raise awareness. Partnerships between governmental, economic and scientific stakeholders may well be the political entities that can cause change. One of the most ingenious and physically daunting mitigation methods employed so far is called reef restoration. In this method, coral polyps are bred and then planted on reefs that have been bleached. The new corals are bred to withstand rough handling by humans and must be proven to “take” when planted. Success has been seen in Pacific and Caribbean reefs using this new, exciting technology. Some feel the future is bright for reef restoration. Other scientists are pessimistic, however. They feel that planting by hand simply takes too long and doesn’t cover enough territory fast enough (Normille, 2009). Understanding and rebuilding the food webs that surround coral reefs is another way to improve the health of a reef. The role of large, herbivores on the reef is an important one. They eat algae that compete with the symbiotic algae the coral polyp requires for life. Unfortunately, many of these herbivores are also the prize catches of the fishing fleets of the world. A global approach to rebuilding these fish stocks is underway (Boris Worm, 2009). Unfortunately balancing the demands of high species diversity, high yields and high employment is beyond the ability of any one group of concerned scientists. Nearly 60% of the earth’s fish stocks need to be rebuilt. One way this rebuilding can be accomplished is by establishing No Take Areas (NTA’s). These areas not only help rebuild the fish stocks, but they offer good opportunities for scientists to study the recovery of reefs damaged by direct human contact. Protecting coral reefs is obviously a good idea. We depend on them in many ways. They offer habitats for beautiful creatures that also help sustain human life. Global warming will need to be addressed soon if we are to save these special places from further degradation. Work Cited Alley, R. (2003). Abrupt Climate Change. Science , 2005-2010. Boris Worm, e. a. (2009). Rebuilding Global Fisheries. Science , 578-585. Carpenter, e. a. (2008). One-third of reef-building corals face elevated extinction risk from climate change and local impacts. Science , 560-563. Death, G. (2009). Declining Coral Calcification on the Great Barrier Reef. Science , 116-119. Halpern, B. S. (2008). A global map of human impact on marine ecosystems. Science , 948-952. Hoegh-Guldberg, e. a. (2007). Coral reefs under rapid climate change and ocean acidification. Science , 1737-1742. Hughes, e. a. (2003). Climate change, human impacts, and the resilience of coral reefs. Science , 929-933. Normille, D. (2009). Bringing coral reefs back from the living dead. Science , 559-601. Normille, D. (2007). Warmer waters more deadly to coral reefs than pollution. Science , 682-683. Pandolfi, e. a. (2005). Are u.s. coral reefs on the slippery slope to slime? Science , 1725-1726. Ricciardi, A. (2006). How protected are coral reefs? Science , 214. Stone, R. (2007). A world without corals. Science , 678-681. Vanderstraete, T. (2004). Remote sensing as a tool for integrated management of coral reefs in the red sea. Retrieved October 27, 2009, from ISPRS: www.isprs.org/publications/related/ISRSE/html/papers/341.pdf Read More