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alternative energy technologies an introduction with computer simulations pdf

1.1 Global Warming
In the US there is a curious divide between how conservatives and liberals perceive global warming. It might seem strange that science is politicized (being
based on objective and observable truths), but the American media is often
partisan and antagonistic which leads to polarized and biased perceptions. In
particular, conservative media refer to an “academic liberal conspiracy” where
they believe scientists are lying about global warming, and seek to undermine
climate scientists and their research. In effect, the conservative media (and
the industrialists and businessmen who fund such media from profits derived
from fossil fuels) have made it difficult for conservative politicians to advocate
adopting alternative energy sources (at least if they hope to be re-elected).
However, global warming is obviously real and here we will briefly consider
the science behind global warming and the potential environmental impacts
that global warming might have upon our world.

The earth’s climate is variable, not just on a local scale, but globally across the entire planet. At the center of this variability is an energy balance between the energy incident on the earth from the sun, and the energy radiated back out to space. In other words, there is a radiation budget between the incident radiation (which will depend on factors such as how reflective our planet is and
how bright our sun is) and radiation being emitted back out to space (depending on factors such as the temperature of the planet and how much outgoing thermal radiation is trapped by the greenhouse effect). The components that influence this energy balance can have severe and devastating impacts on our planet’s climate and ecology, and is at the heart of our existence on this planet.

The energy coming in to our planet comes from the sun. This is primarily in the form of light in the visible spectrum and ultraviolet. The high temperature of the sun means that it emits these higher frequency (shorter wavelength) and more energetic electromagnetic radiation. In particular, the temperature of the surface of the sun is roughly 5500 oC and the sun gives off a tremendous amount of energy (of which only a very small fraction is directed towards the earth). Some of this light is reflected back out into space, from clouds in the sky or from ice on the ground, for example, but some of this energy is absorbed by the earth, heating up the surface of our planet. The fraction of light which is reflected back out to space is called the albedo.