We are living in specially remarkable moments in the history of mankind. One of the biggest issues facing this planet this decade is global warming. Its effects on animals, plants and agriculture in general are indeed, frightening. The potential negative effects on human race are even more scaring. Interestingly, despite the obvious evidences of its existence, it is a subject surrounded by lots of controversies. Some people, in fact, believe that it is not real and argue that it is simply a scientific exaggeration. The facts about global warming continue to be debated on, but unfortunately, even if we do not find consensus on its causes, its effects are not only real, global, but also measurable.
However, most people do agree that the warming trend is real and that carbon dioxide and other greenhouse gases are contributing to the problem. There is also general agreement that industrial activity is affecting climate by causing an increase in average global temperatures-this idea is now widely accepted and reported as a fact. While debates continue among scientist, environmentalists and members of the media fraternity, something drastic must be done to address what has now come to be touted as the biggest global environmental threat facing mankind.
This paper seeks to explain why global warming is real by critically reviewing and appraising current literature on global warming, its effects and evidence of its existence. In essence, the paper contends that global warming is real, measurable and global. A survey was also carried out to establish the level of people's knowledge concerning global warming whose results are included in the appendix.
Background to Global Warming
Global warming forces the inclusion of scientific concepts. It is ironical that people trust science in most other disciplines like medicine yet disputes it when it comes to climate changes. Medications and medical research are readily acceptable and people largely embrace modern technology to improve quality of lives and increase productivity. Yet, raise the truth underpinning global warming and suddenly, people begin to raise eyebrows questioning the validity of science! The roots of the confusion more accurately lies in the term "global warming" and the emerging climatic trends that scientists have well documented. In fact, it is simply a twist of fate that the complexity of this phenomenon lies in its naming. To be precise about the effects of global warming as evidence of its happening, it is more so like trying to draw the most impeccable and accurate map. Perhaps, only a map drawn to scale of one to one can be termed as the most accurate representation. Unfortunately, the same analogy strongly applies in explaining global warming.
In order to fully comprehend the popular global warming debate, one must appreciate the distinction between the greenhouse effect and the enhanced greenhouse effect (Ungar 298). This is the primary cause of contention. Well, scientists largely agree on existence of greenhouse effect that causes the earth to be warm. This effect is explained by the fact that carbon dioxide, nitrous oxide, water vapor and methane are transparent to the short wavelength radiation from the sun but opaque to the longer wavelength radiation emitted from the earth (Crowley 272). In very simple terms, green house gases trap the heat from the sun and this is why the earth grows warmer. As such, the popular debate on global warming concerns whether humans, through their additions of green house gases to the atmosphere, do contribute to the green house effect that occurs naturally. Studies have proved that the effect of these greenhouse gases has been enhanced by human activities (Grinberg). As such, this provides a strong inference about how increases in carbon dioxide in the atmosphere will tend to warm the planet-global warming.
Evidences of Global Warming
An uniformed observer of climate change would be forgiven to argue that there has been no significant climatic changes over the years. The issue has been treated with a lot of speculation and skepticism especially by members of the media who has blown its controversies out of hand, often convincing its audience that there is little agreement among scientists about the greenhouse effect. Yet, much of the theory about human-induced climatic change has never been, or at least is no longer, in contention. This is because much of the basics of the science of global warming and its effects have long been understood many years ago. By the end of 1980s, many scientists around the globe had actually concluded that adequate evidence of global warming had been known. The rate in which humans were changing greenhouse gas production justified the assertion that global warming was rapidly threatening existence in the planet (Crowley 274).
Since then, the scientific community has greatly reduced many of the uncertainties. Assessment on climatic changes has concluded that the continued hardly predictable weather changes, ocean temperatures, melting of glaciers and ice caps unequivocally show that global warming is happening (Smith 19). Essentially, the effects of climatic change usually vary in respect to the host of certain-site conditions such as topography, land cover among others. As such, to reduce climatic change or more accurately, global warming to a single cause and effect is indeed, far too simplistic. Several evidences continue to surface in our everyday lives. These includes global temperature changes, sea level rise, ice cap melting and glaciers and the general alteration in ecosystems which indisputably show that global warming is real and happening.
Change in Global Temperatures
Studies on past climates show that the relative stability over the last hundred years has been unusual. However, the average global temperature has changed only slightly though with significant effects. For example, a slight cooling of 40C would take our planet back to the "last ice age" while warming by the same magnitude would perhaps create a hot and wet climate of the "Cretaceous Period"-when dinosaurs ruled the world (Barze and Thomas 270). The earth planet continues to experience unprecedented increase in temperature. This is a key indicator that indeed, global warming is here with us. The climate system itself is probably responsible for most of the warming we have seen in the last 100 years or so (Slocum 764). Contrary to the popular thought, you do not require a change in the sun or perhaps a volcanic eruption or even pollution by the human race to cause global warming. Warming can too, occur naturally.
Fortunately, we have satellite-measured evidence of this self induced climate change. Even though having actual measurements of the source of climate change is far much doing better, the theory of manmade global warming still strongly holds grounds. It is therefore, important to substantiate these claims. The reason why many people doubt validity of evidences on global warming is because they think of "global warming" as synonymous with "manmade global warming" (Linder 106). In reality, the human activities only serve to enhance the effect of greenhouse gases. The alleged connection between global warming and human activities has unfortunately, become so firmly entrenched in our minds that even scientists doubt their own scientific findings!
All in all, significant warming and other climatic changes have occurred over the last 100 years are validated by many diverse data sets. When for instance, the last 100 years are compared with the last 1,000 years, it is very clear that something completely different is happening. The evidence suggests that the natural climate forces such as sunspots and volcanic eruptions have been similar for the last millennium (Energy Information Administration 13). Essentially, this leaves only one alternative, that greenhouse gases, known for their radiative force, have already influenced global climate. This has been supported by many climatologists. For example, Barze and Thomas contend that in the light of the new climate change evidence, and while considering the remaining uncertainties, most of the observed increase in temperatures is to a higher degree, due to the increase in greenhouse gas concentration in the atmosphere (271). The key variables used in assessing this include land surface air temperature, sea surface air temperature, and air temperature over the oceans. All these climatic studies have concluded that the last decade is the warmest since eighteenth century (Slocum 779). Since scientists rely on statistical data analysis from which they reach conclusions. This is also the basis for science whereby a question is raised and an experimental study is done to provide an answer. In this regard, it would not only amount to ignorance but also intellectual hypocrisy to doubt the validity of the very science we believe in, in other disciplines.
Sea Level Rise
Grinberg laments that our cities are sinking! This is because global warming has caused temperatures to rise tremendously and therefore, the world's large cities and coastal regions are more exposed to its negative effects. In a recent study, seasoned panel of researchers cautioned that sea levels are projected to rise by more than a foot in the next century (Grinberg). This was a comprehensive study where satellite data map was used to map out regions with elevations below thirty feet above the sea level since they constitute the regions considered to be at higher risk of global warming. More disturbing news was also presented by another intergovernmental panel of climatologists who behold doubt proved that coastlines were already showing the effect of sea level rise (Grinberg). To make the matter worse, the panel warned that more than 100 million people could be flooded by the rising seas annually by the year 2080. In addition, America's two largest cities-New York and Los Angeles, are not only at higher risk of the rising sea levels but also prone to experience violent storms meaning that the megafloods that are usually experienced in North America once in a century could occur as regularly as every three to four years (Smith 24). In addition, the severity of hurricanes and cyclones is frightening. As a result, environmentalists have come up with the most formidable and firm evidence that global warming is and will significantly amplify the intensities of the storms worldwide. Crowley explains that the maximum wind speeds of tropical cyclones have increased considerably since 1980s and cautions that unless global warming is put at check, the upward trend is unlikely to stop in the near future (275). These storms have in return, negative effects on sea water levels.
Scientists, however, feel that this is only statistical projections and that continued global warming could as a matter of fact, cause more damages than expected. As such, the rising sea level is matter of concern for major urban cities of the world for two reasons. One, these high population density, that further magnifies effect of human activity on global warming, and secondly, because such cities are developing hubs for commerce, manufacturing and economic development. In addition, by making the sea rise, global warming has created big problems for many animals, plants and people living on island regions. Over the years, we have continued to witness water covering plants and causing some to die, animal losing source of food and their habitats. Evidence of global warming in respect to the changes in the oceans is both expansive and elusive. Many things are happening in the oceans today that can only be linked to global warming (Antilla 349). For example, the warm water as a result of global warming is not only harming but also killing algae in the oceans further creating severe food shortage for many animals in the sea.
Ice Melting and Glaciers
Some of the firmest evidence for global warming is perhaps, being experienced in the Arctic. Even though many people appear to believe that global warming is a big hoax, there has been declining snow cover as seen in the North polar-the ice has thinned significantly. Apart from the thinning, it has been observed that the ice cap is too shrinking (Slocum 778). This means that the ice that has taken many years to build up is melting away each passing summer. Moreover, in each fall and winter, the multilayered ice cap is continuously being replaced by more thinner freshly built ice. Normally, thin ice layers are more vulnerable to warm temperatures and of course, melt at a faster rate as compared to the multiyear ice. In this respect, global warming has caused the thinner ice to shrink each year leaving the multiyear ice highly vulnerable.
This trend has been witnessed largely in the last one decade and it is not just data obtained from satellite as the National Snow and Ice Data Center (NSIDC) has also shown the similar trend about the Arctic sea ice since late 1970s (Smith 20). In addition, computer models by both NASA and other scientific authorities have unanimously predicted sea ice decline in the coming years as the dark side of global warming continue to be experienced. In fact, some environmentalists argue that the observed changes in the last decade have happened faster than any of the computer models could predict (Antilla 344). Other countries such as Denmark and India with monitoring stations focused on the Arctic sea have also confirmed that effects of global warming are quantifiable. Climatologists have closely related the consequences of global warming with the emerging glaciers and ice melting while remaining uncertain on the magnitude this could have on the global weather in years to come.
Ecosystems around the World Have Been Altered
The world has in the recent time experienced unprecedented changes in the overall ecosystems. There has been massive crop failures which is only attributable to climatic change or more accurately, global warming. Recent studies show that over 3 billion people across the world will have to move their families to milder climes or alternatively go hungry owing to climatic change within the coming 100 years (Smith 19). This is because global warming has had severe consequences on water supplies. As its effects continue to unravel, shortages in rainfall are more likely to reduce food production, sanitation and damage ecosystems considerably. Global warming has specifically caused violent swings between drought and floods with approximately three hundred deaths resulting annually due to its effects (Smith 21). Another indicator of ecosystem alterations is the widespread extinction of species. Animal behaviour studies have related the rising temperatures with extinction of species in excess of one million (Slocum 766). Global warming, today represents an undeniable threat to a number of species currently surviving on earth due to continued habitat modification.
Another indicator of global warming is the disappearance of coral reefs. Studies have shown that coral populations will collapse by the year 2100 owing to the increased ocean acidification and temperature rise (Smith 26). This is especially a severe threat to ocean ecosystems. In short, it is only a matter of time before warming waters and increased acidification make coral reefs the first world ecosystem to disappear. Also, the stationarity of ecosystem is dead-the thinking that natural systems fluctuate within unchanging envelope of variability (Milly et. al 573). This has been compromised by the both human and climatic disturbances especially in river banks. In other words, significant anthropogenic change of global climate is continually altering the means and extremes of precipitation, transpiration, evaporation, and rates of discharge of rivers. It has been concluded that global warming is solely responsible for this since warming augments atmospheric humidity and water transport often causing seasons of drought and floods. Unfortunately, Milly et.al argues that stationarity cannot be revived, even with the most aggressive mitigation procedures due to the continued global warming, increased greenhouse gases and the thermal inertia of earth system (573). All in all, the direction global warming is likely to take depends largely on human activity and mitigation efforts.
In conclusion, scientists have provided firm and well supported evidences of global warming. Their arguments and research findings are too well understood. Whether by natural means or human activity, increase in greenhouse gases is largely responsible for warming the surface of the earth. However, global warming does not necessarily mean that that there is universal warming across the globe, or postulate an end to predictable weather patterns. In essence, weather patterns are functions of extremely complex processes, and if unchecked, the effects of global warming could be horrific and terrible. The effects will be frightening irrespective of which systems are disrupted first, and even though we may experience relatively stable climates, global warming is not a hoax; its effects are real and will continue to be experienced globally.