The Global Warming and Coral Reefs - Report Example

CORAL REEFS &CLIMATE CHANGE WHAT DOES THEFUTURE HOLD? Prepared by: Essex Prescott – 40495111 Sean Cooper - April 10, EOSC 315 Sec 99C Michael Lipsen The focus of the scientific articles: “ENSO Drove 2500-Year Collapse of Eastern Pacific Coral Reefs” (ENSO) (Toth et al, 2012) and “Coral Reefs Under Rapid Climate Change and Ocean Acidification” (CLIMATE) (Hoegh-Guldberg et al, 2007) is the prediction of the deleterious effects ofglobal warming on coral reefs. These research papers attempt through looking at the past and compiling existing research to test and predict the future effects of climate change on coral reef health and accretion. They conclude that a high potential for collapse of coral reef ecosystems in the future is possible which clearly demonstrates the need for immediate action along with further research. This analysis will examine in detail the purpose of the research, the methods used, summarize the findings, analyze the results in relation to its importance to both oceans and humans and ends with future considerations for proactive management responses and policy change. Overview One of the most productive, diverse and valuable ecosystems on earth (Notes), coral reefs are the highest primary producers of all ecosystems. They are storehouses of immense biological, economic and cultural wealth and are thus of great importance and the subject of hundreds of research papers, global symposiums, monitoring networks (Jackson et al, 2012). The focus of both papers is to predict how the increasing sea temperatures and ocean acidification can lead to the collapse of these systems in the future. Both papers discuss the mechanisms at play including increasing temperatures resulting in more bleaching events and disease along with ocean acidification from increased CO2 uptake reducing reef growth and calcification. It is evident from these research papers that climate variation and rates of change of CO2 are the drivers behind the potential collapse and point to the anticipated future global warming scenarios leading to such collapse as predicted by the Intergovernmental Panel on Climate Change (ICCP) (ICCP, 2007). It is just a matter of when and where. Research Methods The first paper ENSO delivers a paleo ecological approach by investigating the history of the Pacific reef building framework and comparing it to current trends in climate variation and CO2 emissions. This primary field research consisted of obtaining push core samples from reef habitats in the Pacific Panama region. From these samples, the researchers could then clearly define a hiatus in coral reef growth 2500 years ago by observing a drastic change in the type of sediments in the sample core. The samples showed a clear shift from coral building skeletons to non-building coralline algae rubble. This data is then correlated with a time of the large swings in ENSO exhibiting as El Nino and La Nina events along with coupling with the Intertropical Convergence Zone (ITCZ). The second paper, CLIMATE primarily focuses on interpreting other data specifically from the Vostok Ice Core study (5) and the EPICA (6) study. There is limited field study included in this paper predominantly proving the trend of carbonate accretion as CO2 rises. Rates of change are important in this paper as it concludes that “ modern….corals do not appear to have the capacity to adapt to sudden environmental change” (Hoegh-Guldberg et al, 2007). This research paper then models a coral dominated equilibrium versus an algal-dominated equilibrium different system and the combinations of coral cover and grazing that permit each. Finally, the authors use ICCP climate change scenarios, to produce three predicted scenarios for coral reefs over the coming decade. Here, they are using proxy data to interpolate or predict trajectories of coral recovery, stasis or degradation. Findings Both papers achieve consistent conclusions predicting devastating consequences for coral reefs under even the most conservative future global warming scenarios. They both also call for the need for further research and immediate proactive responses and management to the situation. ENSO concludes that climate variability was the controlling influence on the hiatus in reef accretion in the Pacific during the Holocene. The paper compares the current variability in ENSO and the future plausible climate change scenarios to that of the Holocene hiatus and concludes that it is “probably” driving eastern Pacific reefs to another collapse. This research dispels other hypotheses of the cause of Holocene hiatus: 1) high sea levels drowning the reefs of necessary light; 2) reefs filling the available space; 3) tectonics and 4) bio erosion. They further combine their research with interpretation of other researchers’ data to conclude that this is a Pacific-wide phenomenon. Climate change predicts three different scenarios; a static, a midrange and a high CO2 emission rate using ICCP scenarios. Under the static scenario, the conclusions are that reefs will continue to change and be distressed but will remain coral dominated, albeit by temperature resilient corals, assuming local conditions such as water quality and fishing pressure are controlled. The midrange scenario predicts a vast loss of biodiversity in the ecosystem, a higher incidence of coral disease and bleaching events resulting in an overall decline in the reefs ability to grow and compete for space. The high scenario prediction is that the reef will collapse and half or even more of the reef fauna will become extinct. Reefs will not be able to adapt to this level of change nor recover from the long term effects. Analysis& Future Considerations To summarize the findings, the conclusions are based on proxies and association rather than demonstrated cause and effect since causality is not yet definitely established and future variability is based upon predictions.. Considering the consequences and these findings, it can be observed that they are based on the most plausible and credible scenarios available with historical pinnings and they are sufficient to act upon. The scientific community has accepted the overall conclusion of climate change having a deleterious effect on corals and these studies further support this overall conclusion (Oreskes, 2004). However, there are some shortcomings that should be addressed. The effect of the coupling of the ITCZ with the climate oscillations was important to the conclusions drawn about the hiatus in the Holocene. However, there is no discussion of the potential for the strength of this coupling occuring in the future. Since increased ENSO activity occurred as the transition out of the hiatus without the ITCZ influence, it appears important to provide some prediction of this coupling in the future. These studies either hold constant or are silent to the model prediction of natural modes of climate variability and other causal ecosystem influences such as urchin density, fish abundance etc.. Note that the disease afflicting urchins in the 1980’s in the Caribbean had a tremendous negative impact on current day coral reef systems in that area (Hoegh-Guldberg et al, 2007). Donner in his review of the modelling efforts to predict the future of coral reefs considers the following; “Therefore, the reliability of future projections for coral reefs will depend on a model’s ability to represent such natural modes of climate variability in the existing climate and the response of those natural modes of variability to human-induced climate warming,” (Donner et al, 2005). Further on this topic, Professor Connolly who leads the Coral Reef Biodiversity Program at the ARC Centre for Coral Reef Studies suggests that we need models that vigorously inspect the fit of the data to get good estimates of the future predictions. Off the shelf models used in previous analysis are inappropriate. Finally, these future scenarios predict emissions of CO2 but not concentrations. The ocean uptake of CO2, ranges greatly in the research. The predictions need to consider the response of the earth’s ecosystems. Currently, the predictions of temperature rate increases will still be lower than the highest rates of change seen in history. This is not the case for CO2 rates to rise which now far exceed any time in history (Pandolfi, 2015). So are these predictions underestimating the potential consequences and or positive feedbacks? Importance to Oceans and Humans These studies and the prediction of future consequences are critically important to promote proactive management. The highest primary producers, coral reefs are one of the most important ecosystems on earth. Besides the biodiversity and safe harbor they promote within the oceans, they also have a huge economic and sustainability importance to humans. Biodiversity is key to healthy resilient ecosystems but also coral diversity is leading to finding new medicines for cancer, arthritis and human bacterial viruses. Economically, corals provide an estimated goods and services valued at over $375 billion each year (NOAA). Many third world countries rely heavily on coral ecosystems for their food source and main economic gross product. Finally, coral reefs provide natural barriers to beach erosion and protection of sea grass and mangroves as mentioned in the studies. The potential collapse of reef systems are far too great a consequence hence the importance and appropriateness of this research and the awareness it promotes. Conclusion The research studies clearly support the asserion that human-induced climate change is causing the current effect on the coral ecosystem. Although the predictions for future change have a range of possibilities, any of the potential outcomes pose great threat to the coral ecosystems of the globe and people that rely upon them. Although the science is based upon associations and predictions, the results are clear and call for immediate proactive management and intervention to first reduce the human induced climatic changes and build coral reef resiliency. References: Read More