Climate Change.docx

EXERCISE 4: Climate change impacts in a representative aquatic ecosystem: Utilizing long term ecological and meteorological data Department of Biological Sciences College of Science, University of Santo Tomas España, Manila Philippines Abstract Climate change has been prevalent starting from its acknowledgement from the early 19th century. Studying the effects of climate change is a major undertaking especially for the scientific community. An appropriate way of relating climate change to an ecosystem involves differentiation of previous to current states of an environment. Lakes are a good model for such comparison. The relationship between surface water temperature, air temperature, rainfall, and the intensity of tropical storms in Lake Taal were recognized using data analysis.

Introduction The earth being the exclusive domain of every known creature, cause and experience numerous natural phenomena including climate and weather. A climate refers to the long-term pattern of weather in a definite area, it does not fluctuate as much as weather conditions. Customarily, a territory’s weather pattern observed for at least 30 years, are regarded as climate. Changes in climate were given attention during the early 19th century when natural changes in paleoclimate and ice ages were initially presumed and the natural greenhouse effect was also distinguished. Climate change involves various aspects of atmospheric alterations. This results in changes in measure of precipitation, temperature, wind patterns and global warming. An official study done during the 1990’s point to greenhouse gases

and human-caused emissions as the genesis of global warming. The greenhouse effect is not entirely unfavorable for the living state of all forms of earthly life. The greenhouse effect is recognized as either ‘natural’ or ‘enhanced’. The natural greenhouse effect allows life on earth, preventing its average surface temperature from being – 18°C as it is approximately 14°C. The earth’s atmosphere allows light to pass through and traps heat in the process, without the atmosphere such energy will be lost in space. This dynamic is made possible by ‘natural’ greenhouse gases. On the other hand, the ‘enhanced’ greenhouse effect also known as 'anthropogenic climate change’, are human-induced build up in the atmosphere. Starting from the Industrial Revolution, the burning of fossil fuel such as oil and coal mainly lead to the rise of greenhouse gases which caused the slower rate of heat loss within our planet. One of its

negative effects is subjected upon the oceans, with it absorbing more than 85% of the additional heat in the atmosphere. The ‘enhanced’ greenhouse effect supposedly changes basic weather patterns in the climate such as, wind and rainfall patterns and the incidence and intensity of storms. The ever changing conditions of our ecosystem has lead to critical conclusions about the longer effects of climate change, especially global warming. Presently, a maximum rise of CO2 in 800,000 years is being recognized. Making up 84% of all the greenhouse gases, CO2 massively contributes to global warming. The year 2015 was recorded as the hottest year with an annual average temperature of 0.90°C. Continually emitting an excessive amount of greenhouse gases will give a rise to global warming. It is being predicted that for the next two decades warming of about 0.2° C shall take place. Understanding the impact of climate change shall be better grasped through the process of comparing previous to current states of a certain ecosystem. A lake as an aquatic ecosystem serves as a suitable medium for deciphering climate change, with it being susceptible and vulnerable to such phenomenon. In this exercise, the students aimed to make an analysis from an archived data as to how climate conditions within a locale or a region have influenced the environmental conditions of Lake Taal from year 2000 to 2011.

Methodology

Table 1. Monthly averages of surface water temperatures (in Celsius) in Lake Taal from 2000- 2011

Table 2. Monthly averages of air temperatures (in Celsius) and amount of rainfall in Lake Taal from 2000-2011 A graph was created to show the trends in water temperature changes in Lake Taal based on the data listed in Table 1. Possible observable changes in the surface water temperatures in the lake was measured and an appropriate statistical was used. The reporters observed if there are any differences between the mean annual and mean monthly temperatures of Taal Lake.

An air temperature and rainfall in Lake Taal graph from Table 2 was created using the average monthly air temperature readings per month from 2000-2011 from PAGASA Ambulong Weather Station. It was compared with the first graph. A graph was created using the most appropriate statistical tool and software that shows the relationship between the average air temperatures (Table 2) with the average surface water temperatures (Table 1) in Lake Taal. The same process would be used, using an appropriate statistical tool, comparing two variables. In this context, the average monthly temperature reading of the whole country (which is gathered from an external source) was compared to the average surface water temperatures of Lake Taal. Using the said statistical tool, it was used to identify if the two variables have a significant relationship, and assigned the dependent and independent variable from it. The final procedure required another external source. The source gathered is the recorded typhoons / tropical storms that had hit Lake Taal from 2000-2011. Using the gathered source, the number and intensity (in terms of wind speed) was plotted, and observations of any noticeable trends in the date were recorded. Results and Discussion

of

This report presents the development the average monthly surface

temperatures, air temperature, amount of rainfall, and amount of typhoons in Lake Taal and in the Philippines for years 20002011 with the emphasis on the statistical correlation as calculated using the Pearson’s Correlation Coefficient. Utilizing the given data set (Figure 1.1) , a time series line graph (Figure 1.2) was employed to monitor the changes in the average monthly surface water temperature in Lake Taal. It is important to note that most calendar months experience record for all years although there may be some months without records. Year 2009 has the most complete record for all months while Year 2007 has the fewest recorded data. From the graph, it can be observed that Year 2000 have the highest recorded temperature with a temperature of 33.64 °C on the month of May. On the other hand, Years 2002, 2003 and 2008 have the lowest recorded temperature with a temperature of 24.8 °C for the months of March, February and February, respectively. Although the cold months of 2010-2011 have a higher temperature compared to the cold months of 2000-2009, there is no massive increase in temperature for the years 2000-2011.

Figure 1.1 Average Monthly Surface Water Temperatures in Lake Taal

Figure 1.2 Time Series of Average Monthly Surface Water Temperatures in Lake Taal For comparison, the mean annual surface water temperatures and mean monthly surface temperature were plotted in a scatter plot (Figure 2) to show the correlation of the two variables. The linear relationship was calculated in Microsoft Excel using Pearson Correlation Coefficient. The calculated Pearson’s coefficient is -0.57. The computed value is consistent with the graph which shows a downhill linear relationship between the two variables. A negative correlation signifies that the mean annual surface water temperature and mean monthly surface temperature have an inverse relationship; meaning, as the mean annual surface water temperature increases, the mean monthly surface temperature decreases, and vice versa.The linear equation tells us that the slope (m) is 0.2897 and the y-intercept (b) is 37.041. On the other hand, R2= indicates how well one variable predicts the value of another variable. Specifically, the graph shows that independent variable (x- monthly) can predict the dependent variable (y- annual) with 31.9% or 32% accuracy.

Figure 2 Mean Annual Temperature vs. Mean Monthly temperature Another time series graph (Figure 3.2) was also plotted using the data set given (Figure 3.1). The time series graph was the most appropriate graph to observe the changes in monthly air temperatures over the given time period. It is again important to note that some months of the year do not have a record although most months have a complete record. Analyzing the graph, we can see that the highest peak which corresponds to the highest temperature is located at Year 2003. April 2003 has the highest recorded temperature among the given temperature with a temperature of 29.98 °C. On the Other hand, year 2009 have the coldest recorded temperature with a temperature of 25.63 °C on the month of January. Again, there is not much significant changes on the trend of monthly average air temperatures although the year 2011 has colder temperature records compared to years 2000-2010. The amount of rainfall was also plotted using a bar graph (Figure 3.3). July 2002 has the most amount of recorded rainfall with 652.3 mm of rainfall. From the bar graph, it can be observed that the early months and late months of the year has the least amount of

rainfall while the middle months of the year have the most amount of rainfall. In the year 2011, a sudden increase of amount of rainfall all throughout the year can be observed. The year with the most amount of rainfall is 2011 while the year with the least amount of rainfall is 2004. To compare the two variables, the graph was merged (Figure 3.4) It can be noticed that the months with most amount of rainfall has a higher recorded temperature while the months with the least amount of rainfall have lower recorded temperature.

Figure 3.3 Amount of Rainfall in Lake Taal

Figure 3.4 Comparison of monthly average air temperatures and amount of rainfall

Figure 3.1 Monthly averages of air temperatures (in Celsius) and amount of rainfall in Lake Taal from 2000-2011

Figure 3.2 Time Series of Monthly Average of Air Temperatures in Lake Taal

The statistical correlation of monthly averages of air temperature and monthly amount of rainfall in Lake Taal was also calculated using the Pearson’s Correlation Coefficient. The calculated correlation coefficient is 0.99796 which has a perfect positive linear relationship. The calculated coefficient is consistent with the plotted scatter plot graph (Figure 4) because it shows an uphill graph. A positive correlation signifies that the monthly averages of air temperature and amount of rainfall have a direct relationship; meaning, as air temperature increases, the amount of rainfall also increases. This is because the amount of rainfall depends on the amount of water vapour in the atmosphere. When the air has a higher temperature, the atmosphere may contain more water vapour, thus increasing the amount of rainfall.

Figure 5.2 Time Series of Average Monthly Air Temperature in the Philippines

Figure 4 Average Air Temperature vs Amount of Rainfall

The average monthly air temperature in the Philippines from years 2000-2011 was also plotted in a time series graph (Figure 5.2) from the given data set obtained from PAG-ASA’s database (Figure 5.1) The year 2007 has the highest peak or highest recorded temperature with a temperature of 27.35 °C on the month of April while year 2011 has the lowest peak or lowest recorded temperature of 24.02 °C on the month of January. From the graph, it can be observed that years 2009-2010 have colder recorded temperatures than the average while years 2008-2011 have lower temperatures for the cold months compared to years 2000-2007.

Figure 5.1 Average Monthly Temperature in the Philippines

Air

The relationship between average monthly temperatures in the Philippines and average surface water temperatures was also plotted in a scatter plot graph (Figure 6) to compare the two variables. The calculated Pearson’s Correlation Coefficient is 0.91 which shows a positive linear relationship. This computation is consistent with the plotted graph which shows an uphill line graph. A positive correlation signifies that the average monthly temperature in the Philippines and average surface water temperatures in lake Taal have a direct relationship; meaning, as temperatures in the Philippine increases, the surface water temperature in Lake Taal also increases. The linear equation tells us that the slope (m) is 1.6959 and the y-intercept (b) is -15.262. Also, R2= indicates how well one variable predicts the value of another variable. Specifically, the graph shows that independent variable (x- monthly temp) can predict the dependent variable (y- surface water temp.) with 82% accuracy. There is a direct relationship between air and water temperature because of temperature conduction of atmospheric heat transfer on the surface water. Heat flows from higher temperature to a lower temperature.When the air is cold, warm water will transfer energy to the air therefore also increasing the temperature of air. On the other hand, when the air has a high temperature, cold water will receive the energy, thereby also increasing the temperature of the water.

Figure 7.1 Number of Tropical Depression, Tropical Storm and Typhoon in the Philippines from 2000-2011

Figure 6 Average Monthly Temperatures in the Philippines vs Average Surface Water Temperatures in Lake Taal The number of tropical depression, tropical storm and typhoon in the Philippines was also plotted using the bar graph. The bar graph was used so as to easily see the amount of the variables. A tropical depression forms when a low pressure area is accompanied by thunderstorms that produce a circular wind flow with maximum sustained winds below 39 mph. An upgrade to a tropical storm occurs when cyclonic circulation becomes more organized and maximum sustained winds gust between 39 mph and 73 mph. On the other hand, a typhoon is a tropical cyclone with sustained surface winds of 118 to 239 km/hr. From the graph, it can be seen that years 2003 and 2004 has the most amount amount of storms and depression while the year 2010 has the least amount of typhoon, tropical storms and tropical depression. It can also be observed that the year 2007 does not have any tropical depressions at all.

Figure 7.2 Bar Graph of Number of Tropical Depression, Tropical Storm and Typhoon in the Philippines from 2000-2011

Conclusion

At the end of the exercise, the students were able to utilize available data sources for the study of climate change and identified the impacts of climate change to the environment. Referencing the numerous graphs that were plotted from an archived data showing the relationship as to how climate conditions at Lake Taal from years 2000 to 2011 influenced its environmental conditions, it can be said that climate change does take an effect on the aquatic ecosystem since changes from the atmosphere in terms of temperature would give a significant change to the bodies of water. This does not only change them but it may potentially be

harmful to the aquatic ecosystem once the changes come to an extreme rate. As of now, it should be realized that from the data presented, studies and data regarding climate change should be given more attention to prevent further the rate of global warming.