Is Climate Change real? Greenhouse Gases, Climate Science and the Human Outlook
The question of the immanence and character of climate change received attention in the recent Presidential election campaign in the United States. In particular, the candidates debated how to view the growing concern among scientists and many in the general public about rising levels of carbon dioxide (CO2) and other greenhouse gases in the earth’s atmosphere. CO2, a greenhouse gas, has both natural and anthropogenic sources. Some of its natural causes include respiration, decomposition, volcanic eruptions etc. Anthropogenic sources include deforestation, power generation, agricultural practices and burning fossil fuels, to name a few.
Global CO2 levels have been maintained over time by a delicate process known as “The Carbon Cycle.” This is a biogeochemical succession in which carbon, a common element on Earth, is exchanged and recycled through biological, geological, hydrological and atmospheric processes. The carbon cycle occurs across millions of years, or longer. A very small input or output that strays from this fragile balance unleashes a domino effect that affects many other natural cycles and processes, which in turn influence life itself.
There is a misconception that anthropogenic sources are the lone cause of increasing CO2 levels. Natural sources have always been a primary factor raising CO2 levels throughout Earth’s history. But, lately, the release of CO2 into the Earth’s atmosphere by anthropogenic sources has been increasing carbon dioxide levels considerably. Fossil fuel burning emissions, electricity production using fossil fuels and cement production accounted for 91% of human source carbon dioxide emissions in 2014. Deforestation is the second largest human source of CO2 emissions (Van der Werf et al., 2009, 737). While these processes have been emitting increased amounts of carbon dioxide into the atmosphere, the land and ocean carbon sinks have seen a net decrease in the amount of that element they have been absorbing in recent decades (Le Quéré et al., 2013, 177). The main land sink for carbon dioxide comprises forests and other plant life that take in the gas and release oxygen. With increasing deforestation and land use changes, the amount of oxygen release and carbon absorption is considerably lower now than it was in past decades (Van der Werf et al., 2009, 737).
The ocean sink consists of phytoplanktons and zooplanktons that absorb CO2 from the upper ocean and then carry it down to the depths as they sink, thereby becoming incorporated into oceanic sediments. The carbon dioxide then interacts with chemicals in the sediments to form mineral assemblages that sequester carbon naturally for many years (Raven and Falkowski, 1999). Repeated studies have shown that a substantial increase in atmospheric CO2 emissions accompanied the Industrial Revolution (1760 AD onwards). Assuming a steady state in biological carbon processes, an additional 30% increase in carbon intake by oceanic sinks has occurred since the Industrial Revolution (Raven and Falkowski, 1999).
Methane, CH4, another important greenhouse gas, also plays a role in the rise in global average temperatures that is resulting in climate change. Natural sources of CH4 occur mainly in wetlands, which produce about 78% of the chemical. Such marshlands are highly temperature sensitive (Christensen et al., 2004). Fossil fuel burning and livestock farming are important human sources of methane (Bousquet et al., 2006). One of the earth’s largest methane sinks is its permafrost, a thick layer of frozen soil that circles the globe’s poles. Significant spikes in greenhouse gas concentrations in the atmosphere and resulting temperature increases are now causing the permafrost to melt, thereby emitting large amounts of CH4 back into the atmosphere (Christensen et al., 2004).
Increasing greenhouse gas concentrations could also eventually warm the oceans, leading to changes in currents that arise from the deep. This would change the microclimates of local regions that depend on those flows for their ways of life. When the deep ocean warms, this could also potentially release the carbon stored in its upper sediments.
Elevated carbon levels change ecosystems substantially, through direct and indirect effects. Certain plants have been able to adapt and increase their photosynthesis levels as CO2 levels have increased, while others have not been able to do so. Rising carbon dioxide concentrations influence plant flower gestation rates, flowering times, longevity and seed quality. Such conditions are also likely to reduce the number of plant pollinators or change their characteristics (Bazzaz, 1990). Soaring temperatures might also lead to extinction of certain crucial species of plants, thereby changing entire local ecosystems.
Local, state and national governments and international organizations must take responsibility to educate the general public about the crucial and currently observable changes in climate that are already occurring. Existing evidence, samples, records, publications and facts must be assembled and presented in easily communicable ways that intrigue and enlighten audiences at the same time. Governments of all nations must assign science research related to climate change high priority. The recent U.S. President’s proposal to reduce the research budgets of agencies that focus on climate science and related issues is deeply concerning and disheartening. Should budget reductions of the magnitude proposed occur, such action could significantly set back the progress made so far to address climate change world-wide. And, unfortunately, President Donald Trump is not alone in his stance. Climate change doubters and skeptics claim to believe these misguided proposals represent a political “victory” in favor of “sound science.”
The general populace must become aware of the global phenomenon that is climate change and fight to preserve our Mother Earth, not just for us, but also for future generations. As mentioned above, the Earth is able to thrive by balancing delicate interconnected natural cycles and processes. A small imbalance in one cycle can potentially lead to a large counter effect that cascades and changes life and comfort as we know it. The approximately 7 billion people on Earth could make a substantial difference in ameliorating and ultimately reversing climate change if we all unite and take measures to preserve and conserve the bounty that we obtain from our Mother Earth.
I conclude with a quotation from the movie “Interstellar”:
We used to look up at the sky and wonder at our place in the stars, now we just look down and worry about our place in the dirt.
Bazzaz, F.A., 1990. The response of natural ecosystems to the rising global CO2 levels. Annual review of ecology and systematics, 21(1), pp.167-196.
Bousquet, P., Ciais, P., Miller, J.B., Dlugokencky, E.J., Hauglustaine, D.A., Prigent, C., Van der Werf, G.R., Peylin, P., Brunke, E.G., Carouge, C. and Langenfelds, R.L., 2006. Contribution of anthropogenic and natural sources to atmospheric methane variability. Nature, 443(7110), pp.439-443.
Christensen, T.R., Johansson, T., Åkerman, H.J., Mastepanov, M., Malmer, N., Friborg, T., Crill, P. and Svensson, B.H., 2004. Thawing sub-arctic permafrost: Effects on vegetation and methane emissions. Geophysical research letters, 31(4).
Le Quéré, C., Andres, R.J., Boden, T., Conway, T., Houghton, R.A., House, J.I., Marland, G., Peters, G.P., Van der Werf, G., Ahlström, A. and Andrew, R.M., 2012. The global carbon budget 1959–2011. Earth System Science Data Discussions, 5(2), pp.1107-1157.
Raven, J.A. and Falkowski, P.G., 1999. Oceanic sinks for atmospheric CO2. Plant, Cell & Environment, 22(6), pp.741-755.
Van der Werf, G.R., Morton, D.C., DeFries, R.S., Olivier, J.G., Kasibhatla, P.S., Jackson, R.B., Collatz, G.J. and Randerson, J.T., 2009. CO2 emissions from forest loss. Nature geoscience, 2(11), pp.737-738.
Kannikha Kolandaivelu is a second-year PhD student in the Department of Geosciences. She obtained her Master’s degree in Geosciences from the same department. Kannikha earned a B.E. in Civil Engineering at Anna University in India. Her interest in learning more about the inner workings of our planet Earth brought her to Virginia Tech. She is focusing on Thermal Geophysics for her doctoral research. In addition to science she is interested in short-story writing, mostly fiction; authoring blog posts; reading and pondering the purpose of life and human existence.
March 30, 2017