Global Warming and Climate Change

Global warming is in the media so much you would have to have come from Mars to not be aware that it is seen almost universally as a big issue. Almost.

The nature of the problem is seen as follows:

There are fluctuations in temperature across the Earth. Places are experiencing record high and low temperatures and unseasonable climate effects.
These fluctuations are caused by a small increase in average temperature.
The increase in temperature is caused by an increase in carbon dioxide, which causes a ‘greenhouse effect’.
The increase in carbon dioxide is caused by man-made factors.

All the media reports on global warming report factors that affect (1) – that is, that there is climate change across the world. As an example An Inconvenient Truth reports:

The number of Category 4 and 5 hurricanes has almost doubled in the last 30 years.
Malaria has spread to higher altitudes in places like the Colombian Andes, 7,000 feet above sea level.
The flow of ice from glaciers in Greenland has more than doubled over the past decade.
At least 279 species of plants and animals are already responding to global warming, moving closer to the poles.

If the warming continues, we can expect catastrophic consequences.

Deaths from global warming will double in just 25 years -- to 300,000 people a year.
Global sea levels could rise by more than 20 feet with the loss of shelf ice in Greenland and Antarctica, devastating coastal areas worldwide.
Heat waves will be more frequent and more intense.
Droughts and wildfires will occur more often.
The Arctic Ocean could be ice free in summer by 2050.
More than a million species worldwide could be driven to extinction by 2050.

Let’s look, purely for example, at the first three items.

The number of Category 4 and 5 hurricanes has almost doubled in the last 30 years.

For evidence the site references a paper by Emanuel, K. This paper actually states:

When coupled with the expected increase in storm lifetime, one might expect a total increase of PDI of around 8–12%, far short of the observed change.

He then goes on to explain some other factors and concludes:

…This is still short of the observed increase.

In other words, the increase in temperature cannot account for the rise in hurricanes.

Malaria has spread to higher altitudes in places like the Colombian Andes, 7,000 feet above sea level.

Many papers, including this one dispute that the spread of diseases is increasing or if it is that this is caused by global warming.

The flow of ice from glaciers in Greenland has more than doubled over the past decade.

The paper sited actually gives no suggested cause.

Most scientists agree that The Earth's average near-surface atmospheric temperature rose 0.6 ± 0.2° Celsius (1.1 ± 0.4 ° Fahrenheit) in the 20th century. However, all the effects sited above would require a fairly large increase in warming to bring about the changes. So the effects sited are not caused by global warming but by climate change.

From an engineering perspective, it is difficult to get an average when there are wide fluctuations in raw data. The wider the fluctuations, the more difficult it is. What is more, temperature data is collected sporadically from around the world and only for the last few years, so to get an average of 0.6° C over a 100-year period with these wide fluctuations is disputable.

So from our original list:

Is probably true
Is disputable. There can be many factors causing the weather changes beside an increase in global temperature
Is disputable. According to this site, water vapour as a greenhouse gas overwhelms carbon dioxide.

So what are we to make of this? Simply don’t believe it to be so just because a number of people tell you it is so. Look for yourself.