Global Warming- Past Trends and Future Projections Investigation by Edward Sun Nepean High School

Background Information Global warming is the increase in the Earth’s average surface temperature. Global warming is caused by the Greenhouse Effect and elevated emissions of greenhouse gases, notably carbon dioxide. Naturally occurring greenhouse gases help regulate the Earth's climate by trapping heat in the atmosphere and reflecting it back to the surface. However, human activities have amplified this natural process.

Background Information (Con’t) In the past century, the mean surface temperature on Earth has increased approximately 0.6 degrees Celsius. Eleven of the last twelve years rank among the twelve warmest years since If global warming is indeed caused by human activities, as suggested by many studies, then all of us are responsible to do something about it.

Seeking An Answer Global warming is becoming one of the central issues of the world More and more people are becoming aware of the undesirable effects global warming could have on the Earth’s climate, due to much propaganda. Global temperatures have been rising and are projected to rise further in the future.

The Question What factors have been causing the Earth’s climate to change, and how will it change in the future? In an endeavour to answer the above question, I decided to investigate on the topic of global warming. As there are two parts to this question, data of past trends will be analyzed, and predictions for the future will be made based on these past trends.

My Hypotheses: In the future, the climate of the Earth will likely be warmer, the sea levels will likely rise, and weather patterns and precipitation will be affected. Human activities such as burning fossil fuels are responsible for past alterations of the Earth’s climate. Conducting research, analyzing secondary data, and studying relationships will help determine the precision of these hypotheses.

Variables Examined What is the relationship between global warming and: The amount of precipitation? The emission of CO 2 ? The number of motorized vehicles? Ocean levels? The amount of fossil fuel burnt?

A Potential Cause As global warming is primarily caused by an overabundance of greenhouse gases in the atmosphere, we will first consider some factors that could cause a rise in the atmospheric concentrations of gases such as carbon dioxide and nitrogen dioxide. What are some things that produce these gases?

A Potential Cause (Con’t) The first to come to mind are cars that line the roads of cities, which are increasing in number every year. Burning gasoline releases carbon dioxide. As the combustion of gasoline is an absolute necessity for cars to run, the number of cars escalating through the years must surely mean that the amount of greenhouse gases entering the atmosphere has been increasing as well.

Below is graph of the total number of registered vehicles in Canada from year 1990 to 1995: The total number of registered vehicles in Canada had been increasing at a steady rate in the six years.

Canada’s economy was gradually growing, and the number of cars on the roads had been on the rise at an average rate of 1.33% each year. Now let us examine what effects this had had on the emissions of greenhouse gases in Canada.

There was an increase in Canada’s emissions of greenhouse gases at the same time as the number of vehicles was mounting.

= suggests that the increase in the number of vehicles may be causing a rise in the amount of greenhouse gases released into the atmosphere. When we study the same relationship for the United States, we find similar, positive correlations. When graphed onto the same axes, the strong, positive correlation

Canada and the United States are selected in a cluster sample of countries in North America, as they are the dominant producers of greenhouse gases. Since it is shown by many studies that global warming is indeed caused by the Greenhouse Effect, we may be able to say from studying the above relationships that manufacturing more cars will contribute to global warming. However, as there are many other factors that can cause the Earth’s climate to change, we cannot conclude with certainty that the increase in the number of vehicles has caused significant changes to the concentration of greenhouse gases in our atmosphere.

Burning of Fossil Fuels Burning fossil fuels is another major contributor to atmospheric carbon dioxide concentrations.

As we can see from the pie chart in the previous slide, about 75% of the world’s energy is produced by burning fossil fuels. Let us examine how this affects global warming. Here is a graph displaying the total fossil fuel CO 2 emissions in Canada between 1985 and 2004.

Clearly, an increasing amount of carbon dioxide is being released from burning fossil fuels. Now let us compare it with the temperature trend in the Northern Hemisphere between 1960 and 2005.

As much as the temperature deviations fluctuate, we can see from the linear trend line that the average temperature had been steadily increasing. The graph in the next slide clearly shows the cause-and-effect relationship between the two variables.

It appears that the amount of fossil fuels burnt also has a strong, positive correlation with the rise in temperature. From studying the statistics, we learn that burning fossil fuels has indeed been producing more and more carbon dioxide each year. Since there is much evidence proving that global climate change is due to elevated levels of greenhouse gases in the atmosphere, it is fair to say that burning fossil fuels is definitely a contributing factor to the global temperature rises.

Recent Trends and the Future Despite much propaganda attempting to raise global awareness regarding global warming, the number of cars continues to increase, as do the sales of gasoline.

If we extrapolate on the graphs, we can easily predict that in about five years, the sales of gasoline in Canada will exceed 39 billion litres per year, while the sales of diesel oil will surpass 20 billion litres per year. The implications of this are clear without saying: more greenhouse gases will be produced, which may lead to further changes of the Earth’s climate.

Now let us look at how the climate has been affected so far. On the following page is a graph on the average annual rainfall amounts in Canada between the years of

While there were great variations in the average yearly rainfall amounts during this decade and half, we can see from the negative slope of the trend line that on the whole, rainfall amounts had been decreasing. If this trend continues, then further drops in the amounts of rainfall can be expected. We can clearly see this by extending the trend line on the graph.

On A Global Scale So we have seen that alterations in the climate of the northern hemisphere have been occurring. Let us see if changes are also taking place on a global scale. If the global temperatures have indeed been getting warmer, then we can expect to perceive visible changes in the Polar Regions, where a rise in temperature can cause the ice to melt. Examining the graph on the following slide allows us to see the changes that had been occurring in the Arctic ice thickness between the years of 1990 to 1997.

As we can see, the sea ice had indeed been melting and getting thinner over these seven years. Because global temperatures have been climbing constantly, we can conclude that the ice melting is due to global warming.

Another question arises from this conclusion: What happens to the sea level as the ice melts? The logical answer is that it will rise. Let us see if this is true.

As predicted, the sea levels are indeed rising. This can also be attributed to the global climate changes, as we have already concluded that global warming is what causes the ice to melt. Let us examine a recent set of data: YearRise in Sea Level (cm)

Assuming current trends will stay the same in the future, the likelihood of the Barents Sea level rising more than 10 cm in a future year is 4/6 or 67%. The probability of the number of years the Barents Sea rises over 10 cm in sea level in the next twenty years can be shown by a binomial distribution:

# of Years the Barents Sea Level Rises Over 10 cm (x) P (x) 0 20 C 0 (0.67) 0 (0.33) 20 = 2.35X C 1 (0.67) 1 (0.33) 19 = 9.53X C 2 (0.67) 2 (0.33) 18 = 1.83X C 3 (0.67) 3 (0.33) 17 = 2.24X C 4 (0.67) 4 (0.33) 16 = 1.93X C 5 (0.67) 5 (0.33) 15 = 1.25X C 6 (0.67) 6 (0.33) 14 = 6.37X C 7 (0.67) 7 (0.33) 13 = 2.59X C 8 (0.67) 8 (0.33) 12 = 8.53X C 9 (0.67) 9 (0.33) 11 = 2.31X C 10 (0.67) 10 (0.33) 10 = 5.16X C 11 (0.67) 11 (0.33) 9 = 9.52X C 12 (0.67) 12 (0.33) 8 = C 13 (0.67) 13 (0.33) 7 = C 14 (0.67) 14 (0.33) 6 = C 15 (0.67) 15 (0.33) 5 = C 16 (0.67) 16 (0.33) 4 = 9.47X C 17 (0.67) 17 (0.33) 3 = 4.53X C 18 (0.67) 18 (0.33) 2 = 1.53X C 19 (0.67) 19 (0.33) 1 =3.27X C 20 (0.67) 20 (0.33) 0 = 3.32X10 -4

As we can see from the chart from the previous slide, it is most likely that the sea level of the Barents Sea will rise over 10 cm in 12 to 15 years of the future twenty years, if the current trend continues. The expected number of years E (x) is 20X0.67= 13.4 years. Now let us calculate the probability that the Barents Sea rises over 10 cm in ten or more of the twenty years ahead. Since np=20X0.67=13.4 and nq=20X0.33=6.6 (both greater than 5), it is reasonable to use a normal distribution to approximate. The mean (μ) will be np=13.4, and the standard deviation (σ) will equal to (npq) ½ =(20X0.67X0.33) ½ =2.1

P(x > 9.5) = 1 – P(x < 9.5) = 1 – P(z < (9.5–13.4)/2.1) = 1 – P(z < -1.86) = 1 – ≈ 0.97 The normal approximation shows that the likelihood of the Barents Sea rising over 10 cm in ten or more of the twenty future years is about 97%. This high probability is also an indicator of how much the global climate has changed, and how much it will continue to change if the current trends persist.

In Conclusion Strong, positive correlations have been found between the atmospheric concentrations of greenhouse gases and some human activities that produce such gases. Analyzing climate patterns allowed calculations to be done on the likelihood of further climate changes. These calculations show that it is extremely likely for the Earth’s climate to continue changing in the future. Looking at the obtained results, it seems that global warming has indeed been caused by human activities, and the Earth’s climate will likely experience further changes, as stated in the hypothesis

Con’t Although the gathered statistics all strongly support the hypothesis, they do not confirm its precision. While it is extremely probable that the hypothesis is correct, the fact remains that there are numerous other factors that can contribute to the greenhouse effect, and many organizations around the world are taking action to slow, if not stop global warming.

Bias in the Data Data were collected from trustworthy websites to minimize the number of results that are skewed due to various forms of bias. However, in some cases the sample sizes may have been too small and may not be representative of how the climate of the entire globe has been changing.

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