Essay: Greenhouse gases – how their effects shape populations & biodiversity of geographic regions

Introduction
Greenhouse gases can be defined as, gases in the atmosphere (such as water vapour, ozone, CO2, NO2 and CH4) that absorb longwave radiation emitted by the earth and contribute to the greenhouse effect. This means greenhouse gases selectively absorb radiation from the Earth’s surface and re-radiate as heat. Therefore, the greater amount of greenhouse gases in the atmosphere, the greater amount of radiation will be trapped. Furthermore, as stated in the article by Yousef Najjar, “the surface of the earth, which warms up during the day as a result of the absorption of solar energy, cools down at night by radiating part of its energy into deep space as infrared radiation… [greenhouse gases, such as carbon dioxide and water vapour] act like a blanket and keep the earth warm at night by blocking the heat radiated from the earth.” (Najjar, 2010). By creating this thick blanket of greenhouse gases around the atmosphere we are essentially trapping more radiation. Figure 1.1 shows an illustration of the greenhouse effect and how excess amounts of greenhouse gases allow for more radiation to be kept in the atmosphere.
Figure 1.1 shows that greenhouse effect and how radiation emitted from the Earth is trapped in the atmosphere increasing the heat retained.
The main objectives of this paper are to briefly highlight what greenhouse gases are, the effects they can have, how these effects shape populations & biodiversity of certain geographic regions (i.e. competition for resources, distribution, migration etc.).
Climate is expressed as the long-term average pattern of weather in a given area, local, regional or even global. Climate change on the global scale has become a major concern to many in recent history, with some main driving points being global warming, rising ocean levels, habitat destruction and increased extreme weathers (storms, hurricanes, etc.). As stated by Althor et al., “the current generation is the first to feel the effects of anthropogenic climate change. Despite their well-known harmful impacts to the world’s climate system, greenhouse gases (GHG) are deliberately emitted by countries to drive economic growth and enhance human wellbeing.” (Althor et al, 2016) Some major causes of climate/weather related issues, such as rising average temperatures, rising sea levels and increased precipitation patterns, can be linked with the emissions of greenhouse gases. The unfortunate consequences of these climate/weather related events include, species not being able to find food, having to flee from specific environments due to destruction of habitats, and in some cases, species becoming endangered or even facing extinction.
Effects on the arctic
As the Earth heats we experience many concerns with respect to biodiversity, one of them being the rise in ocean levels & melting of glaciers impacting the species living in the arctic. “Climate change is already having an impact on biodiversity and is projected to become a progressively more significant threat in the coming decades. Loss of arctic sea threatens biodiversity across an entire biome and beyond.” (Shah, 2014) Performance curves can be used to determine the ranges within which a species can survive, grow and reproduce respectively. Such is the case in the arctic environments, with the rise in temperatures and ocean levels disabling certain animals from feeding and reproducing effectively. For example, constantly melting and freezing ice conditions effect the living circumstances of both seals and polar bears as “normally, ringed seal pups are born under snow drifts [which] the polar bears can dig through with relative ease. But [recently], seals appeared to be pupping under the ice because of altered sea ice conditions.” (Allsopp et all, 2012). This situation allowed the seals to find new conditions to birth their children (favouring them), whereas the polar bears (at a disadvantage) now work harder to reach their prey. Figure 1.3 displays the conditions the polar bears are currently facing. In this case we see how the polar bears have reduced energy efficiency as a result of abnormal hunting behaviours, as well as reduced availability of prey, and increasing competition amongst existing individuals of the population. Furthermore, melting ice also has an effect on denning strategies of pregnant polar bears. Warming conditions result in, changes in the degree consolidation of the ice making it less suitable for denning, instigating the pregnant bears to shift to land masses before birthing. Switching to land, however, does not solve the problem as this change in itself has its own repercussions some of which are mentioned by Fischbach et al, “The females must be able to walk on the ice or swim to the land to reach the denning area. However, because the distance in autumn between the southern edge of the pack ice and the coastal areas is increasing with climate change, this distance may become too great for the pregnant females to cross” (Fischbach et al, 2007). Not only polar bears but walruses have also experienced a drastic decrease in population size as a result of increasing sea levels and rising temperatures. As a result of shrinking ice, walruses have lost a major portion of their habitat and thus have also been added to the list of endangered species since 2011. These findings show that there is no “winning” in this situation and these arctic animals are finding very hard not only to reproduce but also just to survive.
Figure 1.3 Shows the effects altering sea ice conditions have on the availability of food for the polar bears. The conditions cause the bear top to spend more energy in trying to find food therefore its weak appearance.
Ocean Acidification
The increased acidification of the ocean as a result of increased CO2 is also another major threat created greenhouse gas emissions, in this case to the biodiversity of aquatic animals. The majority of the CO2 emitted into the atmosphere, is absorbed by the ocean resulting in the decrease of its PH levels. The mechanism by which the PH decreases is explained in the article by the ocean portal team “when CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. This increase causes the seawater to become more acidic.” (The Ocean Portal Team, 2018). As the ocean acidifies the carbonate ions, which are important to structures such as shells and corals, become less valuable. It makes it extremely hard for calcifying (shell using) organisms such as oysters, clams and calcareous plankton to build and maintain shells necessary for their protection. As a result of these consequences we may see smaller populations of such animals, which in the long run can relay them to be overexploited by their prey, eliminating them from the ecosystem. Another possibility of could be that the predators themselves cannot detect these animals because of new appearances (no shells), which in turn could prove to be harmful for the predators by reducing their food source. In any case, the food chain of aquatic animals is affected as a result of acidification. This disruption may also affect the people who harvest these fish not only for consumption but for their economies, as they now would have to adapt and find different sources of food and income or migrate, decreasing the biodiversity of the area. “Overall, [acidification] is expected to have dramatic and mostly negative impacts on ocean ecosystems- [even though] some species (especially those that live in estuaries) are finding ways to adapt to the changing conditions.” (The Ocean Portal Team, 2018).
Figure 1.2 shows that mechanism by which increased CO2 levels in the atmosphere cause decreased carbonate ions in the water resulting in fewer calcifiers.
Plants and herbivores
Finally, greenhouse gases may affect the growth rates and biodiversity of plants and associated organisms. Although some might think that increasing greenhouse gases, such as carbon dioxide (main component photosynthesis), must be beneficial to plants, we cannot take away from the other negative aspects they bring. As the earth heats up, we get more depletion of essential resources, such as water (during times of droughts), which can then decrease the moisture levels of the soils restricting the rate of photosynthesis. Another issue increasing temperatures can have is denaturation of certain proteins. Since plants are not homeotherms the regulation of their temperatures depends on the environment they are in, and if the temperatures are too high it can cause harmful effects on the enzymes necessary for photosynthesis, an example being rubisco binding to O2 instead of CO2. Not only do these gases decrease their ability to grow but also degrade the nutritional value the plants. Samuel Myers, research scientist in environmental health at Harvard, noted that “We know unequivocally that when you grow food at elevated CO2 levels in fields, it becomes less nutritious, … atmospheric CO2 levels predicted for mid-century—around 550 parts per million—could make food crops lose enough of those key nutrients to cause zinc deficits in 150 million to 200 million [people].” (Sneed, 2018) Furthermore, “Numerous studies have already documented shifts in the timing of plant growth at high latitudes associated with recent climate change” (Post and Forchhammer, 2007). These shifts in timing of growth can cause trophic mismatches to occur between herbivores which could then later have negative impacts on survival and reproduction patterns as it would change the performance peaks for these populations. So not only do greenhouse gases have an effect on the plant species but also those that use plants as their carbon resource
Conclusion
The increasing and rising levels of greenhouse gases in pour atmosphere is alarming, even though it is clear that they pose issues to many environments in our ecosystems. The effects they have on climate & weather, growth patterns, and resource availability shape how populations survive and how they are forced to adapt or face extinction. It is a major concern that needs to be addressed on the worldwide scale and there are many small ways us as individuals can address the problem. Increasing public transport (reducing driving), walking, recycling more, and using less plastic are just some small examples we can follow to help reduce the emissions. It is our responsibility to ensure that we create sustainable energy to reduce the emissions of these gases or face the major consequences to the biodiversity.