Is Energy Important?

Energy is necessary for our everyday lives. Energy is used for everything from heating water to running our cars. A large portion of this energy is powered by fossil fuels. Different economies use different amounts of energy, and in different areas. These fluctuations can be due to geographical differences, differing cultures, and varying technologies amongst other things. The energy use breakdown for Hong Kong can be seen in the figure below, as discovered by the Electrical and Mechanical Services Department (EMSD).

A more detailed breakdown by the different areas that use this consumption and what it is being used for can be seen below. Figures such as these prove to be important because it shows which areas are consuming the most energy, thus revealing which are areas that need to be focused on for reducing energy consumption.

The Greenhouse Effect For Dummies

One of the most problematic side effects of fossil fuels is the lasting effect it has on our planets ecosystem, commonly referred to as the greenhouse effect. This is a natural effect that arises from the planets absorption of thermal radiation given off by the sun. The sun emits solar radiation that passes through the earth’s atmosphere. Naturally some of this radiation is absorbed into the Earth, giving a warming effect, while other is reflected off. Greenhouse gasses play a significant role throughout this process because they also absorb some of the sun’s radiation, and then emit the radiation back into the Earth’s atmosphere.  The Image below provides a visual representation of this effect.

The highest contributor to this greenhouse effect is Carbon Dioxide which is given off from the use of fossil fuels. Currently, with the burning of such large quantities of fossil fuels, more and more of these greenhouse gases are building up in the atmosphere. This results in additional radiation being re-emitted back to the Earth, providing a warming effect. Hence, the Greenhouse effect. In Hong Kong specifically, CO2 is the overwhelming Green House Gas that is being emmited, as can be seen in the figure below.

The effects on the environment without changing the current energy profile

The current energy consumption profile is shown on the figure below. 80.3% of the energy produced in the World is fossil fuel. Fossil fuels are non-renewable and will eventually run out. Also, since fossil fuels are carbon based, when burned CO2 is released into the atmosphere.  The technology available today should be used to create more efficient ways of obtaining renewable energy, rather than better methods of fossil fuel extraction.  Increasing renewable energy usage will cut down on CO2 in the atmosphere, thereby reducing the greenhouse effect. Without changing the current energy usage profile, CO2 will continue to be pumped into the atmosphere at an unsustainable rate, thus increasing the temperature of the planet. This affect, although it sounds relatively harmless, can wipeout coastal cities and have devastasting effects on marine life.

Figure :  http://www.personal.psu.edu/kdh5039/Assignment6/Assignment6.html

The Three Components of Sustainability

                            

The ability to meet the needs of the present generation, while not compromising the ability to meet future generations’ needs.  Social, Ecological, and Economic were deemed “The Three Pillars” of sustainability at the 2005 World Summit.  In order to be sustainable, all three requirements must be met. If something is using very little resources and is socially acceptable but not affordable, clearly it can not be considered sustainable. The figure above shows the different ways resources can be used and what is considered sustainable.

What else affects the Earth's climate?

Because there are so many other factors that affect the climate other than human actions, it can be beneficial to group them based on whether they help warm or cool the Earth. These factors are also known as "forcings." If a forcing helps warm the Earth, it is a positive forcing. This includes things such as solar flares and sun spots, volcanic activity, and the release of greenhouse gases into the atmosphere such as the burning of fossil fuels. A negative forcing then helps cool the Earth. One of the major negative forcings is the polar ice caps, which reflect a lot of solar radiation back towards space. As the Earth continues to warm, the ice caps are beginning to melt and break apart, increasing how quickly the Earth warms. Other negative forcings include actions that decrease the concentration of Greenhouse gases in the atmosphere, such as reforestation. The new plants take CO2 out of the atmosphere and return oxygen. A major factor is the Earth's albedo, or how well it reflects solar emissions. With the melting of the ice caps, the Earth's overall albedo is decreasing, allowing the Earth to warm at an increasing rate.

What proof is there that humans are the cause?

Some skeptics may ask for scientific proof that human activities are causing the increase in global average temperatures, and not natural effects. As shown in figures 1 and 2, the global average temperature and CO2 emissions begin to take off around 1900-1910. When compared to levels from the past obtained by ice sampling, tree-ring analysis, and other methods, it can be seen in figure 2 that in the past 100 years, changes have occurred that normally would take hundreds of thousands of years, and corresponds to when the the industrial revolution took place. The concentration of CO2 in the atmosphere is nearly 30% higher than has ever been  seen in history. This evidence leads to the conclusion that natural causes cannot have caused these kinds of changes so rapidly.

Figure 1

(http://data.giss.nasa.gov/gistemp/graphs/)

Figure 2

(http://www.fs.fed.us/ccrc/primers/climate-change-primer.shtml)

Figure 3

(http://climatechangedownunder.wordpress.com/page/2/)

Figure 3 shows the temperature variation with the CO2 variation from the past 800 thousand years obtained by ice core sampling. The data shows that a change of 100 parts per million (0.01%) of carbon dioxide concentration corresponds with a change of 10 degrees Celsius in average global temperature. Today's high concentration of carbon dioxide (highest ever recorded in over 800 thousand years) will undoubtedly cause drastic changes unless something changes. They also show that human activity causing increases in the carbon dioxide levels, such as the burning of fossil fuels, is causing irreversible changes to the Earth's climate.

Why is the Earth's temperature increasing?

The Earth's temperatures have been slowly increasing due to the Greenhouse effect. When solar radiation reaches the Earth, it is able to pass through the atmosphere because of it is high frequency radiation. Some of this radiation is then reflected back towards space at a lower frequency. Greenhouse gases, such as carbon dioxide and methane, in the atmosphere trap the low frequency emissions, and release them in random directions. As more Greenhouse gases are put into the atmosphere, less of the reflected heat from the sun is able to get to space, so the Earth gets warmer and warmer.
The ability of a greenhouse gas to trap heat over a certain amount of time is measured as it is compared to carbon dioxide. This is known as the Global Warming Potential of the gas. For example, methane has a 20 year GWP of 72. This means that if equal weights of carbon dioxide and methane were put into the atmosphere, over 20 years the methane would trap 72 times the amount of heat as carbon dioxide. Although carbon dioxide does not warm the earth as much, it is the largest percentage of the atmosphere. Carbon dioxide also is the gas with the most emissions from human activities such as the burning of fossil fuels. This is why when talking about global warming carbon dioxide is the gas most talked about.