Arguments Against Anthropogenic Global Warming
Global Warming and the Oceans
One of the foremost arguments against anthropogenic global warming is that if global temperatures rise/fall then, after a period of years, the carbon dioxide levels rise/fall accordingly. The oceans are the largest producers of carbon dioxide in the world; they act as reservoirs into which the CO2 goes when it leaves the atmosphere after these temperature shifts. Because of this, if the oceans were to heat up, carbon dioxide would emit and, similarly, if the oceans were to cool down, more CO2 would be dissolved. However the fluctuating of temperatures in the oceans takes years; this is the cause of the consistent time lag in the change of CO2 levels. It is thought that to remember shifts in climate so well, the oceans must have a ‘memory of temperature changes’ running over many years. Scientists say that if this is the case then we are currently experiencing the CO2 increase after a period in the 1940s where temperatures rose by over 0.5 degrees Celsius. This would mean that humans cannot be blamed for global warming, as the temperature rises occurred at a time when CO2 emitting inventions were not used as intensively as they are now. The reader should bear in mind that I collected this information from Channel Four television programme, “The Great Global Warming Swindle”, which has been subject to accusations of misrepresentation.
Graph showing the time lag between temperature increases and rising CO2 levels
Global Warming and Solar Activity
Another point against humans causing global warming is the theory that solar activity sunspots (a region on the Sun's surface that is marked by a lower temperature than its surroundings and has intense magnetic activity) cause changes in the Earth’s temperature. In 1893 the British astronomer Edward Maunder noticed that during the period known as the Little Ice Age, there were almost no sunspots. New research has shown that the sun’s radiation has increased by 0.5% since the 1970s.
Richard Wilson, a Columbia university researcher said that “This trend is important because, if sustained over many decades, it could cause significant climate change." A recent study by Swiss and German scientists proposed that increasing radiation levels from the sun are to blame for climate change. Dr Sami Solanki, the director of the Max Planck Institute for Solar System Research in Germany, who led the study said: "The Sun has been at its strongest over the past 60 years and may now be affecting global temperatures. The Sun is in a changed state. It is brighter than it was a few hundred years ago and this brightening started relatively recently - in the last 100 to 150 years." Solanki went on to say that this increase in the Sun’s output along with greenhouse gases contributed to the increase in global climate. To decide the Sun's function in global warming, Dr Solanki's research team measured magnetic zones on the Sun's surface known as sunspots, which are believed to intensify the Sun's energy output. The team then went on to study sunspot data going back several hundred years. They discovered that the pattern indicated that an absence of sunspots signalled a cold period and that over the past century the number of sunspots had increased as the Earth's climate grew steadily warmer. As human activity has no effect on the Sun, this theory rules out human responsibility in global warming. The source of this information was a website called “space.com”, it is backed by scientists and various other science based websites. However the particular article that I used to find this information was written 2003 which could mean that evidence has since come out to disprove it.
Graph illustrating increases in Earths temperature correlating with increasing sunspots. ...
In 1996, near the last solar minimum, the Sun is nearly featureless. By 1999, approaching maximum, it is dotted by sunspots and fiery hot gas trapped in magnetic loops.
ARGUMENTS FOR ANTHROPOGENIC GLOBAL WARMING
Global Warming And Ice Core Data
Through the study of ancient ice cores from Antarctica it is possible to gauge concentrations of carbon dioxide in the atmosphere. In June of 1999 ice core data from the Vostok site in Antarctica was published. The new data showed us temperature variations and atmospheric concentrations of CO2 and other greenhouse gases back to 420,000 years before present. The main significance of the data lies in the correlation between concentrations of carbon dioxide in the air and temperature, with fluctuations in one plot closely mirrored in the other for the whole period. Look at the graph below. Notice how CO2 concentration rises vertically at the end of the time series. The increase appears vertical because of the large time scale, but it actually occurs over the past 150 years, which corresponds to the industrial age, a time when fossil fuels were used by humans in great amounts. The basis of this information was the website . While not from a particularly well known site, the article had an extensive list of its sources of information at the bottom of the page stating where the data came from and when. This is however, ice core data from the year 2000 so the evidence could, potentially, be out of date.
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Global Warming And Industry
Global warming believers deem human industry and its use of CO2 producing fossil fuels to be the main cause of climate change. However, there is the still the question of whether these emissions are entirely due to human activity. From the data below we can assume that the answer is yes, because it shows that carbon dioxide levels have been increasing since the 18th century, the time of the industrial revolution. Anthropogenic carbon emissions and atmospheric carbon dioxide concentration are also shown in the graph below. Current emissions are almost 7 billion metric tons per year. Current carbon dioxide concentration is about 360 parts per million. Although these two curves follow a similar growing course, they are not in close conformity except during the last 2 decades. The reliability of my source could be questioned due to the fact that the information was published in 1998. And, although the article contained a lot of technical language, it was from a relatively unknown website.
Anthropogenic carbon emissions (green circles) and atmospheric carbon dioxide concentration (red squares) from 1900 to present.
Conclusion
After gathering and taking into account all of the above arguments, I can summarise the evidence both for and against anthropogenic global warming. The main arguments used by global warming sceptics are that the Earth’s oceans are releasing CO2 into our atmosphere and that sunspots are causing the increase in global temperatures observed over the last 35 years. On the other hand, global warming believers consider human industry to be to blame for the increased CO2 and thus the increase in temperature. They have data from ice cores found in Antarctica to back up their ideas whilst the doubters’ ideas are more difficult to investigate and evaluate. Partly because of this the general public is more familiar with the pro-global warming theories and accepts them as fact more easily.
I consider each side of the argument to be scientifically sound with enough evidence to prove its reliability. Personally, I would like to believe that global warming is not down to human activity, but equally that we can do something to stop its potentially catastrophic effects. Even if we are not entirely to blame, our carbon emissions must have contributed to some extent to the current level of CO2 in the atmosphere. Because of this we can work to reduce our use of fossil fuels and do our best to help our damaged environment.
The evidence for anthropogenic global warming:
The oceans are releasing the temperature increasing CO2.
More sunspots=warmer
Humans have no control over the sun
Fewer sunspots=colder
Both believable although also both just theories
The evidence against anthropogenic global warming:
Ice core data indicates that the industrial age was when the increase in CO2 started.
Human industry…..as above
More like established but just because we are more familiar with the theories. Far less controversy.
suggestion that the oceans store of CO2 being responsible for the increase in global temperatures seems quite realistic and logical although the source I
