This week Bilkent News interviewed the Dean of the Science Faculty, Prof. Hasan Erten on
global warming and its effects. Prof. Erten earned his M.Sc.in Chemistry from the Middle
East Technical University in 1967 and his Ph.D. from the Massachusetts Institute of
Technology (MIT) in 1971.
Bilkent News: Prof. Erten, what is global warming and what are the
possible causes of it?
Prof. Erten: First of all, we should start by understanding the
"Greenhouse Effect," which has been present on Earth since before the first
appearance of humankind within the timescale of evolution. Carbon dioxide (CO2) and other
greenhouse gases such as water vapor (H2O), methane (CH4), and nitrous oxide (N2O) warm
the surface of the Earth naturally by trapping the reflected solar heat in the atmosphere.
Without this effect, our planet would be too cold to be habitable and for living things to
survive. However, global warming is different. After the Industrial Revolution of the last
two centuries, CO2 production rapidly increased in a relatively short period of time. Due
to the burning of fossil fuels such as coal, gas and oil in ever increasing amounts, we
dramatically increased the amount of CO2 in the atmosphere and consequently the average
temperatures are rising. Deforestation for residential and commercial purposes also
contributes to global warming by decreasing the oxygen (O2) concentration thereby
increasing the levels of CO2 indirectly.
B.N.: You mentioned "greenhouse gases." Why are they so
important? And which of them are more influential on the atmospheric and oceanic
temperature rise?
Prof. Erten: Geenhouse gases, such as water vapor, methane, CO2 and ozone
(O3), are naturally present in atmosphere. Greenhouse gases absorb heat radiation coming
from the surface of Earth, keeping the world warmer than it otherwise would be. Industrial
activities result in the release of CO2, methane, nitrous oxide, and chlorofluorocarbons
(CFCs) into the atmosphere in increasing amounts. Among all of those gases, CO2 is
documented to account for over 70% of global warming because of its much larger-scale
production.
B.N: How much warmer is the world likely to become? What is the impact of
global warming?
Prof. Erten: There is not a consensus, but it is projected that "by
the time a baby born today is 80 years old, the world will be some 11 degrees warmer than
it currently is." Biodiversity and the ecological food chain may be threatened,
possible droughts and famines may happen, and thus agricultural production may decrease,
sea level increase may be an issue and freshwater resources may be partially lost.
B.N.: The increase in sea levels… What is the cause of it, and what
might be the effects?
Prof. Erten: The rise of the sea level is a result of the melting of ice
covering the Earth due to global warming. The centuries-old Arctic and Antarctic ice
glaciers, and also the Greenlandic ice will contribute to the sea level increase after
melting, and numerous islands in the Pacific, Atlantic and Indian Oceans might experience
substantial loss of land in some deltas. Therefore global warming threatens some small
island states, which are in danger of sinking.
B.N.: How long does carbon dioxide gas tend to remain in the atmosphere?
Prof. Erten: There is natural carbon dioxide already found in the
atmosphere. Nevertheless, "anthropogenic" activities cause excessive emission of
CO2 to the atmosphere, far above its natural levels. The level of CO2 tends to increase
with time, and it is thought to remain for some hundred years in the atmosphere.
B.N.: Are there any efforts worldwide to prevent, or at least minimize or
slow down, global warming? What can we do individually to combat global warming?
Prof. Erten: Global warming is a "global" problem. Every
individual should work in order to decrease the amount of CO2 emitted to the atmosphere.
Strict emission guidelines should be agreed upon by all countries and should be strictly
enforced. There are many efforts to prevent global warming, and the Kyoto Protocol is a
treaty symbolizing these worldwide efforts. In December 1997, the Kyoto Protocol was
prepared in order to reduce the greenhouse gas emissions of developed and developing
countries to their previous levels. However, two of the largest contributors to global
warming, the United States and Australia still resist abiding by the rules brought by this
protocol, claiming that their economies will suffer from its application. As individuals,
we have a lot of work to do. Energy efficiency and saving at work and home should be the
top priority, because minimizing the waste or losses through proper insulation and saving
methods can decrease our personal CO2 emissions. We can purchase “green” energy
sources wherever available, encourage the use of fuel-efficient public transportation
systems instead of private cars. We can also ride a bicycle for short distances, or walk.
B.N.: What is your opinion about the future? What changes do you expect?
Prof. Erten: The effects of global warming have been observed starting in
the 20th century. These effects were increases in average surface temperature, decrease in
snow and ice cover, and the sea level increasing.
In order to predict future global warming effects, several scenarios were developed using
computer models. Without specific policy changes, the projections for the next century
include "mean temperature increase of 1.5 to 5.8 oC, further decrease in ice sheets,
sea level increase of 9 to 88 centimeters, and climate change. After 2100, human-induced
global warming effects are projected to persist for many centuries and the sea level will
continue to rise for thousands of years. Therefore our work is urgent.
B.N.: Thank you for this edifying interview.
Erkan Bayır (MBG/III)
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