The Physics of Climate Change

As well as being an environmental issue, climate change is a question of physics. Understanding the major problem that is climate change requires research in areas of physics such as energy and radiation.

We start by looking at how the earth stays warm, this starts with the sun. Electromagnetic radiation such as visible and ultraviolet is provided to the earth by the sun. to compensate the energy gained by the earths surface, infrared radiation is emitted from the earth going into space r being traped by greenhouse gases. The energy increase on the surface of the earth causes a significant temperature increase which can be modelled by the Stefan-Boltzmann Law.

What are these greenhouse gases trapping the earths radiation? This is explained by the Greenhouse effect. Gases in the atmosphere such as CO2, CH4, and water vapour absorb the infrared radiation emitted from the earths surface. When this energy cannot escape into space, it is re-radiated back to the earth’s surface. The effect of all this radiating energy is an increase in the Planet’s temperature. Physics has explained the problem we are experiencing! The burning of fossil fuels resulting in a growing amount of Greenhouse gases is the reason for global warming.

How is CO2 making such a big impact when it only makes up a tiny fraction of the earths atmosphere? Physics can explain this too, CO2 molecules have an excellent capacity for absorbing specific wavelengths of radiation reflected from the Earths surface. The effect of this trapped radiation is to trigger other issues, more water vapour in warmer air leads to an increase in Greenhouse gases, melting ice results in a significant decrease in the reflectivity of the earth meaning more heat is absorbed by the earth.

The imbalance in the radiation entering and exiting the Earth’s atmosphere causes warming of the oceans, atmosphere and ice. The large amount of heat absorbed by oceans provides a key indicator of climate change, this being the increasing temperature of the Earth’s oceans.

Physics can predict the future! Physical laws such as energy conservation and radiative transfer can aid in constructing models to predict the response of the Earth to the increasing quantity of greenhouse gases. Physicists predict approximately twice the temperature increase we have already experienced so far by 2100!