1.

The Earth is not cooling rapidly due to the presence of carbon dioxide. The burning of fossil fuels produces carbon dioxide which is the key to turn on the water vapour positive feedback. The presence of carbon dioxide will accelerate the existing water vapour feedback. Tropospheric air temperature will increase due to the rise in the level of carbon dioxide. This causes the saturation vapour pressure to increase which means the capacity of air to hold water vapour becomes larger. Since water vapour is a GHG, it will absorb infrared radiation. Some of the radiation is radiated back to the surface, making the surface warmer. The surface temperature elevates, hence, the Earth isn’t cooling.

2.

The statement in the cartoon is not justified. The greater amount of snow during winter cannot justify the fact that the severity of global warming is decreasing. In fact, it could be the opposite. Research has shown that global warming, also known as climate change, can cause even harsher winter. This is because the warming of oceans and the melting ice caps lead to more water being evaporated into the atmosphere. The increased amount of moisture in the atmosphere is released through precipitation from the clouds in the form of rain, hail, sleet or snow. Therefore, this means when the snowfall level is increasing, it could mean that the global warming effects are being exacerbated.

3.

The working principle of a radar system is that it has a transmitter to emit radio waves in a designated directions. When the radio waves come into contact with an object they are usually reflected in many directions. The radar signals that are reflected back towards the transmitter are the desirable ones that make radar work. Wavelength of the radio and the shape to target object are two key factors that affect radar waves to scatter in different ways . If the wavelength is much shorter than the target’s size, the wave will bounce off in a way similar to the way light is reflected by a mirror. If the wavelength is much longer than the size of the target, the target may not be visible because of poor reflection.Early radar devices developed during world war II used very long wavelengths that were larger than the targets and thus received a vague signal. Therefore the design failed to detect its target. The absorption of microwave radiation by water in the atmosphere interferes with the detection of intended objects. As a water molecule (H2O) has a large permanent electric dipole moment, its positive and negative charges are not centered at the same point; it behaves like a few equal and opposite charges separated by a small distance.

4.

In the short run, I believe that the air quality poses the most serious problem for us. This is because air quality can change drastically within a short period of time. This is evident in the haze that affected Singapore during the June 2013. The air quality of Singapore plunged within days, and caused major disruptions in the lives of many in Singapore. Why we feel that air quality is the most serious problem for us is also because the effects of poor air quality disturb many of us quickly. The elderly and those with respiratory illnesses were especially affected by the haze, many of them showing symptoms of throat irritation and breathlessness. The immediate effects of poor air quality can be felt by everyone quickly. Hence, showing its seriousness in the short run.

In the long run, we believe that global warming poses the most serious problem. This is because global warming is due to human activities, and are accumulative. Effects such as increased sea levels and decreasing size of glaciers are already taking place. Extreme weather disasters are taking place more frequently in the past 10 years as compared to the previous 10 years. Humans beings are not even close to reversing the trend of global warming. Impacts of global warming are hard to reverse as global warming affects everyone, not just some people of a particular place. Greenhouse gas emissions are increasing and show little signs of abating. Greenhouse gases are gases which trap heat in Earth’s atmosphere, causing Earth to trap heat better than before. This brings about an increase in the temperature of Earth, causing global warming to take place. If greenhouse gas emissions keep increasing, it is definitive to say that global warming will continue to take place. Only when greenhouse gases emissions show signs of decrement, then can we say that the global warming is being mitigated. But for now, greenhouse gas emissions continue to top record highs year after year, global warming would thus be the most serious problem in the long term.