Global Warming Background Information

"The planet is warming up and its going to get worse"

CO2 graphs

Global Warming Myths and Facts

Climate Change is driven by many factors operating in unison. The most powerful factors include; tectonic activity such as the uplift of mountain ranges and changes to oceanic circulations; and fluctuations in the orbital perturbations of the Earth. Changes in the angle of tilt of the Earth's axis and the shape of the Earths orbit around the Sun contribute considerably to the amount of solar radiation directly warming the planet.

Greenhouse gases such as carbon dioxide, nitrogen oxides, methane, halocarbons, ozone and water vapour warm the planet by reflecting emitted infra-red radiation back to the Earth. Carbon dioxide is of particular importance because atmospheric concentrations have increased considerably over the last century or so.

Fact: The Earth's climate is warming.

Myth: Human carbon dioxide emissions are small in comparison to natural processes and so cannot be considered a major influence to climate change.

It is true that in comparison to many natural processes, anthropogenic CO2 is not a large input. However, atmospheric CO2 is part of the carbon cycle. A system whereby carbon moves in different forms from rocks (lithosphere) to the atmosphere, to the ocean and through the planets life forms (biosphere). This system of sources and sinks is more or less in a state of equilibrium with a slow trend of increasing or decreasing concentration depending on various factors including the rate of erosion of carboniferous rock, the rate of subduction of such rock into the Earth's mantle, and the global coverage of plant life – especially phytoplankton in the ocean.

The problem with human CO2 is that fossil fuel emissions are effectively a one-way system. The relatively small input of carbon into the atmosphere effectively tips the balance so that the Net CO2 input to the atmosphere increases. Notice that all other inputs to the atmosphere shown in the diagram below, have respective outputs back to the source – all except for fossil fuels.

(Hadley Centre)

Fact: Scientist do not know for certain that human greenhouse gas emissions are driving global warming.

Of course not. Scientists do not know for certain that the big bang happened, or that evolution works in the way Darwin described it. If a scientist gets identical results from an experiment 100 times in a row, he can be almost certain that the next time he will get the same result again, but not completely certain.
At present the best evidence scientists have suggest human greenhouse gas emissions are causing global warming. There is certainly more evidence in support than against and certainly more evidence available than any other contemporary explanation.


Myth: The Earth has been a great deal warmer in the past and so warming is not a concern.

Again as with many myths there is some truth in this statement. However, the temperature of the Earth is not the main problem. The Earth has been a great deal warmer in the past. Around 50 million years ago there were no ice caps, and tropical forests covered much of the arctic circle. However, the climate change that brought about such global temperatures took thousands of years. We are currently experiencing climate change within decades that should be happening on a scale of centuries. The real issue with global warming is the rate of warming.

Fact: There is no debate among scientist about the basic facts of climate change.

The only debate left is the scale of influence that human or 'anthropogenic' CO2 has on climate change. CO2 is a greenhouse gas – this is not disputed. There is a small collection of scientists that debate that other factors such as unusual solar activity are driving climate change at a greater rate than CO2 concentrations. However, at present no other theory has come close to correlating with climate observation and proxy records as closely as CO2 concentrations.

Myth: Global warming will mean warmer weather.

Climate change is not so much about temperature as it is about extra energy in the atmosphere. The warmer the global temperature, the more energy in the atmosphere, the more extreme, and the less predictable the weather. In the UK, we are more likely to experience wetter weather with occasional freak weather events such as storms and sudden heat waves or cold snaps.

Fact: Atmospheric levels of greenhouse gasses have increased considerably over the past century.
Since intensification of agriculture and industry began during the industrial revolution, atmospheric concentrations of methane, carbon dioxide and nitrous oxide have increased dramatically.


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