Global warming causes and scientific evidence for climate change

Global Warming: Fact Rather Than Fiction

The focus of this paper is on global warming and its causes. In the introduction phase, we have given a brief overview of the problem alongside a brief look at the details of the problem itself. It is mentioned here that how much change has actually recorded in the previous decades and what the future might hold on for the planet if the trend keeps on going as it is right now. It has also mentioned the consequences of rise in temperatures which can result in many different scenarios.

We then focused on the causes of the problem and again had a brief overview of it, the causes were divided into two main sections and proper emphasis was given on one of it in order to give the root cause of the phenomena. The discussion phase have a more in-depth look at the causes of global warming, here all the proposed causes and natural events that can lead towards global warming are discussed with a focus on the after effects which the world can face later on.

The main proposed causes are based on actions of humanity which include more and more usage of fossil fuels, deforestation and so on. The natural causes include solar variations, climate change cycle and so on. After the discussion phase we will look at some of the techniques which can help us do better assessment of climate change. Though this is not perfect and is even vulnerable at many cases, it still gives a very good idea of where the climate of the world is heading towards. It is also been stated that more and more new methodologies are being developed and more complex problems regarding this subject are now being touched than they ever were because of advancement in computing technologies available today.

Finally, the conclusion is given regarding global warming in which it is clearly stated that it is a fact rather than fiction and what are the reasons for its existence.

Introduction

In this paper our main task is to discuss global warming as a fact alongside discussing its causes. The global warming phenomenon refers to increase in the average temperature of the Earth's overall atmosphere including its oceans as well as the projected continuation in it. It has been carefully monitored that our planet's average surface temperature has increased by some 0.8 degree centigrade (1.4 degree Fahrenheit) in the last one hundred years, here some two thirds of the recorded increase has taken place in the last three decades.

Scientists from all over the world are on an almost complete consensus that this rise in temperature is because of the increase in the concentrations of the greenhouse gases which are produced through different human activities like burning of the fossil fuel and deforestation. Findings such as these are recognized and recommended by national science academies throughout all of the industrialized world as well as developing countries.

It is further projected by various sources such as the IPCC which is one of the main organizations looking after the climate change that during the current century global surface temperatures are more likely to increase by some 1.5 to 1.9 degree centigrade (2.7 to 3.4 degree Fahrenheit) in their lowest possible amount and 3.4 to 6.1 degree centigrade (6.1 to 11 degree Fahrenheit) in their highest possible amount.

"The increments in global temperatures are expected to make sea levels rise changing the amount as well as pattern of precipitation as well as a possible increment in the size of subtropical deserts." (Doyle 2000). This global warming effect is expected to hit the Arctic the hardest which will result in more retreat of glaciers, sea ice and permafrost.

"Other effects of warming include more occurrences of bad or extreme weather events which include droughts, heavy rainfalls, heatwaves, extinction of different species and so on." (Johansen 2002). Let's overview some of the main causes of global warming, if we take an in-depth analysis of the entire situation then we can easily divide the root of the problem into two groups, firstly the man-made causes and secondly the natural causes. Let's first have a look at some of the natural causes.

As by their title, the natural causes are those which are caused through nature. These include the continuous release of the methane gas from the arctic tundra as well as from the wetlands. Methane gas is defined as a greenhouse gas and it is known to trap heat at the earth's atmosphere causing the whole planet to be warmer than usual. Another natural cause suggests that our planet goes through a climate change cycle, this cycle lasts about forty thousand years.

These were some of the natural causes that can be attributed towards the main root events for global warming, other cases which are man-made and which are more likely to be the main culprit include the following reasons.

Pollution comes in different sorts of shapes and sizes, here burning the fossil fuel is a major factor which causes pollution. The fossil fuels are made of the organic matter like coal or oil. When these fossil fuels are burnt they result in giving green house gas known as carbon dioxide (CO2). Besides this the mining process of oil and coal allows the methane gas to be released in the atmosphere, this occurs because methane is naturally found under the earth's surface and digging for fossil fuel can result in release of methane as well.

Other man-made cause includes overpopulation of the human race, with more people demanding more food as well as more means for transportation. This means more and more extraction of methane as there will be excessive usage of fossil fuels. "More agriculture can also contribute to more methane released as it is found in the manure of the farm animals." (Sim 2009).

Also, it is an established fact that the economies of the Far East nations such as China and India are growing at a rapid pace for the last couple of decades and will carry on this growth pattern for many more years to come. This growth comes at a huge price in terms of environmental issues and it is seen here that in order to power up a major economy the government requires major natural resources such as coal or oil. It is these resources which help in bringing up the necessary growth patterns as well as to support the livelihood of millions of individuals. All of this contributes towards a changing environment that is destined to affect not only the Far Eastern region of the planet but the whole world in general.

Economic growth also translates into more financial power in the hands of ordinary citizen, for example in China the average per capita income was around five hundred dollars two decades ago and it now stands at more than three thousand dollars. This increase in income also makes the people to do more consumption regarding the usage of various different resources that contribute towards a larger carbon footprint for the general population. As a result, we see the continuous shift of climate patterns especially in China.

There have been many cases of breathing problems and other diseases caused by the increment in pollution levels in major Chinese cities which is something the central governing authority still finds tough to fully control. Therefore the economic aspect which is related to the change in climate can not be ignored.

Above are mentioned some of the main causes of global warming, now let's have an in-depth discussion on the subject and look at the methodologies regarding the monitoring of this event.

Discussion

Let's discuss the causes of global warming in more detail here and then look at the monitoring of this entire event in the next section. The recent estimates by NASA's GISS as well as National Climate Data Center give us the info that the years 2005 and 2010 are tied for being Earth's warmest since more widespread and reliable instrumental measurements were made available in the later half of the nineteenth century.

"The observed temperature changes vary differently throughout the planet." (Weart 2003). Since the year 1979, temperatures in land areas have incremented by almost twice as faster as compared to the ocean temperatures which shows a 0.25 degree centigrade per decade increase in land as compared to 0.13 degree centigrade increase in oceans. The temperature at oceans increase slowly because of the ocean's increased and effective heat capacity as well as having the advantage of loosing heat through evaporation. It has also been recorded that the northern hemisphere of Earth is warming more faster as compared to the Southern Hemisphere since it contains more land mass.

Although it is also a fact that more greenhouse gases are emitted in the Northern Hemisphere as compared to the Southern Hemisphere, this specifically does not contribute in the main difference in warming in both of the hemispheres. The thermal inertia of Earth's oceans as well as slow responses of different other indirect effects means the overall climate can take many centuries or even longer to adjust according to the changes in forcing. The Climate commitment studies show that even if the greenhouse gasses are somehow stabilized at the levels observed in year 2000 then a further warming of some 0.5 degree centigrade (0.9 degree Fahrenheit) would still occur.

"The external forcing describes the processes which are external to the overall climate system which influences the climate" (Kemp 1994), here it should be noted that these processes aren't necessarily external to our planet. There are many types of external forces like the radioactive forcing which occur due to the changes in the atmospheric composition, changes in the solar luminosity, the volcanic eruptions as well as the variations in our planet's orbit around Sun.

The attribution of the recently recorded climate change focuses mainly on the mentioned above first three forcing methodologies. The orbital cycles can vary slower over the course of many tens of thousand years, also at the present these are at a relatively cooling trend that would go on to lead the planet towards an upcoming ice age, but the temperature recorded in recent times show a contrasting and increasing rise in worldwide temperatures. It is important to note that this change in climate also affect the marine life in great many ways.

According to scientists if the current trend of warming stays persistent for the next twenty, thirty or forty years then it would result in the extinction of many different species especially those who are associated with the north pole, the polar bear as well as the coral reef are in huge danger because of this change in climate pattern. There have been many forums where this issue of saving wildlife is raised but still much work is needed to be done in order to properly ensure that the next generation of humanity would see the wildlife as seen today.

Let's have a more in-depth focus on the greenhouse effect. It is the process where absorption as well as emission of the infrared radiation by the gases at atmosphere warm up the Earth's lower surface as well as other surfaces. The naturally occurring proportion of greenhouse gases possesses an average warming effect of some 33 degree centigrade (59 degree Fahrenheit). The major greenhouse gasses includes the following types and ratios, water vapor which is known to cause some thirty five to seventy percent of entire greenhouse effect, carbon dioxide (CO2) which causes some nine to twenty five percent effect, methane which causes some four to nine percent effect and the ozone gas which causes some three to seven percent effect.

"The clouds can also affect overall radiation balance at the atmosphere, this can be done through the cloud forcing phenomena which is comparable to the greenhouse gases." (Archer 2010). Let's now have a statistical look at how the human activities throughout past centuries have fueled the global warming phenomena. Since the start of industrial revolution the greenhouse gasses have increased dramatically in the atmosphere.

The amounts of carbon dioxide as well as methane have increased greatly by thirty six percent and one hundred and forty eight percent respectively since the year 1750. These recorded levels are much greater than ever during the previous eight hundred thousand years, whose data has been taken from the ice cores of our planet. Other less direct evidence from geology suggests that the carbon dioxide values much greater than this was in occurrence at about some twenty million years back. Just the burning of fossil fuel has resulted in some three quarters of the increment of carbon dioxide in the past twenty years. "Other reasons for increment in carbon dioxide include changes in the usage of lands, specifically deforestation." (Motavalli 2004).

Also as mentioned before, the gross domestic product (GDP) per capita as well as population growth factor was the root cause of increment in greenhouse gasses, however the attribution of the emissions taken place due to the change in land-use is somewhat disputed among many observers. There have been many emission scenarios designed in order to predict the future in accordance to rising greenhouse levels, the sociological as well as technological developments, the natural developments and so on. In most cases here the emissions are seen to continually rise over the course of the century.

It should also be noted here that the fossil fuel reserves available for humanity are in abundance, and they will not limit the overall carbon emissions in twenty first century. The emission scenarios in cooperation with the modeling of carbon cycle have shown us the estimates regarding the atmospheric concentrations of greenhouse gasses and how they may change in the upcoming future.

By using six scenarios of IPCC SRES, this model suggests strongly that until the year 2100, total atmospheric concentration of carbon dioxide could range somewhere in the middle of 541 and 970 ppm. It shows the increment of 90% to 250% as compared to the year 1750. Let's have a look at the phenomena of global dimming which is related to the global warming problem. Global dimming refers to the gradual reduction in total amount of worldwide direct irradiance at surface of the Earth, this has partially counteracted the phenomena of global warming since 1960. "The main reasons for the dimming are increased volcanic eruptions as well as increment in pollutants due to humans." (Harris 2003).

These pollutants exert a sort of cooling effect by incrementing reflection of the incoming sunlight. Effects of products of the fossil fuel burning and aerosols have greatly offset each other during the recent decades, due to this the warming has occurred because of increment in non-carbon dioxide gasses like methane and although many governments have banned the usage of products which involve the emission of methane yet this still carries on today in great abundance.

The radiative forcing of the particulates is momentarily limited because of wet deposition, this causes them in having the atmospheric lifetime of about a week. The carbon dioxide has a century or more worth of lifetime, so the changes in the particulate concentrations can just delay climate changes because of carbon dioxide. The influences of mentioned particulates which also include black carbon are mostly pronounced at tropical and sub-tropical regions especially in Asia whereas effects by the greenhouse gasses are seen to be more dominant in extratropics as well as the southern hemisphere regions.

Now, let's focus on the phenomena of solar variation and see how it relates to the global warming phenomena. The occurrence of variations at solar output has been one of the main causes of previous climate changes. The overall effect of changes at solar forcing during the past decades is not certain but it is estimated to be minimal with some of the studies even suggesting a small cooling effect whereas others suggesting a small warming effect.

The greenhouse gases as well as solar forcing affects temperatures in many ways. While the increased solar activity alongside increased greenhouse gasses may go on to make the troposphere warmer, the increment in solar activity should make the stratosphere warmer. The increment in the overall greenhouse gasses should make the stratosphere cooler.

A related hypothesis suggests that the magnetic activity of sun deflects the cosmic rays which might influence the overall procedure of the cloud condensation nuclei, this in turn can affect the planet's climate. However, there are other researches as well which have found no concrete evidence relating the warming of the planet in recent times with the cosmic rays.

The overall influence of the cosmic rays at cloud cover is somewhat a factor of hundred lower than what is actually required in order to explain the noticed changes at the clouds or to have a significant contribution in the current and ongoing climate change phenomena. Various other studies from the year 2011 suggest that the solar activity might be slowing, also that the upcoming solar cycle might be delayed.

"The extent of the delay here is not clear though, since the next solar cycle is due in 2020 which might go on to be delayed until 2022 or maybe even longer than that." (Chryssavgis 2012)

Here, it is also a possibility that the solar activity might be going towards Maunder Minimum. So far there is no confirm connection between the global temperature rise and solar sunspot activity, also the scientists who are closely monitoring solar activity study have a belief that the greenhouse gas emissions could halt any cold snap in the future but this theory is not universally recognized. Some scientists also believe that if the solar sunspot activity reaches its peak as predicted according to their calculations then even in that scenario there is no harm to earth.

Some other facts

Here are some of the other facts that prove that global warming is not a myth but a fact which is occurring at an accelerated pace. Today, there exists more carbon dioxide in the atmosphere of the earth than it ever was for the past eight hundred thousand years. Global warming has various different consequences besides the usual warming of the planet, this includes more hurricanes, tornados and massive fires. It is estimated that during the last decade more hurricanes have been developed in the east cost of the United States especially at the Gulf of Mexico as compared to what was expected by the scientific community. More bush fires have also been reported in the jungles of Australia as well as South America and more tornadoes are occurred in the Central United States.

"Global warming is also the cause of huge droughts all across the world" (Keil 1998), the regions that have been mostly affected includes Sub-Saharan Africa, Australia, India, Iberian Peninsula and far eastern regions such as China. These droughts have caused a massive wave of migration and have also caused the deaths of many thousands during the last decade alone. If the current trends continue then the future looks increasingly dim especially for poorer nations all across the globe.

Global warming also tends to raise the rate of illnesses all across the world and as always the poorer nations are the ones which get affected the most, according to some estimates it would be difficult to eradicate polio and malaria now because of the global warming and the United Nations has also admitted that some of its millennium development goals might not be achieved as planned due to the factor of global warming.

Conclusion

In this paper, we have given our assessment on the some of the causes of global warming, it was confirmed that it is a fact and that the human behavior towards the environment is the main reason why there is a change in temperature throughout the world. It is this change which affects every living creature and therefore it is very important to look at the main issues regarding this problem and come up with a solution which is best for the entire planet.

Although nature has its share in the increment of the problem, it is the greenhouse gases and the usage of fossil fuels which is the main cause of this whole problem. If this problem carries on with this rate then it would be devastating for many species and it may even result in extinction of the endangered ones.

The ecosystem is already going through dramatic changes because of global warming, we have seen the melting of glaciers in the Arctic at an alarming rate, which can result in the rise of sea levels throughout the world and those countries which lie below sea levels are most likely to suffer from it. Also, the landscape is changing rapidly and we see more and more deserts appearing or increase in their size throughout the world.

Although there are many techniques used to monitor these events, none can be deemed perfect or near perfect. A climate model depends on five major components and a lack of data provided here means error in prediction. In order to check the system, one must check if it has given correct results regarding the past and then verify them with the actual data available. The human behavior regarding the environment is the main thing which can change the world either for good or bad.

"As sea levels rise, it brings more nations on the brink of drowning down." (Paterson 1996) Countries like The Netherlands and Bangladesh are at the highest risk points and according to some estimates if the sea level rises by more than one foot then more than half of the land mass of these nations could end up under water. Other places which are at high risk because of the rise in sea levels includes Florida, California, the eastern cost of India, Philippines, Indonesia, parts of Thailand and Malaysia and so on.

Due to climate change, less fresh water would be available all across the globe. This could result in low yields of crops, more expensive food for all and food riots occurring in different parts of the globe. Scientists have also come to the conclusion that in the upcoming future fresh water would be very scarce and will probably be more expensive as compared to other utilities. This could result in many conflicts as according to many analysts the future wars could be fought over fresh water resources.

"Scientists also predict that it is highly likely the rainfalls all across the world would be reduced by significant margins." (Mendelsohn 1999). According to some estimates in the next fifteen to twenty years there won't be any rainfall anywhere in the world just because of the factor of global warming and this can contribute more towards the upcoming crisis of fresh water. It is therefore extremely important that the leading nations of the world take concrete actions in solving the global warming problem before it turns into a worst case scenario.