Human Effect on Ecosystems

• Define global warming


  Global warming is a term used to describe a gradual increase in the average temperature of the Earth's atmosphere and surface.
• What is the evidence for climate change?


  Records of carbon dioxide levels - increasing levels of carbon dioxide in the atmosphere are believed to contribute towards climate change as carbon dioxide is a greenhouse gas and is involved in the greenhouse effect. Temperature records which enable analysis of changes in temperature. Pollen in peat bogs - pollen grains are preserved in peat bogs and analysis of samples of pollen can give us an idea of what kind of plants were present at the time when the peat was being formed. Dendrochronology is the study of tree rings as the size of tree rings is affected by temperature. The data can be extrapolated to make predictions which can then be used in models of future climate change. On the other hand, such models have limitations as they do not include factors such as reduction in emission of greenhouse gases.
• What is the Greenhouse effect?


  The Greenhouse effect is the process in which infrared radiation from the Sun is trapped by gases such as carbon dioxide and methane thus leading to an increase in the temperature of the Earth's surface and atmosphere.
• What are the effects of climate change on ecosystems?


  Changes in distribution of species - species would move to cooler areas i.e. northwards. This could potentially lead to extinction of some species due to competition. Changes to development - sex of many reptiles is determined by temperature therefore an increase in temperature would have an effect on the sex ratio of certain species thus potentially leading to extinction. Disrupted life cycles.
• What is CITIES?


  Convention on International Trade in Endangered Species of Wild Fauna/Flora (CITES) It regulates the trade of living organisms and their products by classifying them into three appendices depending on the level of threat to the organism, guided by the Red List.
• Evaluate the effect that CITIES has had on biodiversity:

  CITES has had some success at conserving biodiversity (e.g. ivory trade, sharks, turtle species brought back from the brink of extinction). However, its successes are limited because it deals exclusively with trade, many countries haven't signed up, there is no legal obligation to abide by the rules (only trade sanctions can be used) and commercial interests often override scientific evidence.
• How does conservation maintain biodiversity?


  Conservation serves to maintain or increase the biodiversity within a particular habitat by allowing a sustainable use of the resources, whereas preservation serves to maintain the biodiversity levels and the habitat intact by minimising the effects of human activities on the particular habitat.
• How can the greenhouse effect be mitigated?


  Growing plants to use as a fuel as biofuels which are carbon neutral - carbon dioxide released by burning the fuel is removed from the atmosphere by the plants it is made from. Reforestation to increase the rate at which carbon dioxide is removed.
• Why are sustainability and conservation important?


  Many species provide a source of food and medicine, and are important for processes such as pollination of crops as well as for maintaining a good quality of water as well as tourism. Social reasons include conservation for aesthetic reasons and recreation whereas ethical reasons include the right to survive.
• How is sustainable fishing conducted?

  Sustainable fish stocks: The fishing activity must be at a level that is sustainable for the targeted fish population. The rate of fishing must be = to the rate at which the stocks are replenished. Minimising environmental impact: Fishing operations should be able to maintain the structure productivity, function and diversity of the ecosystem on which the fishery depends. Effective management: The fishery must meet all local, national and international law and must have a management system in place to respond to changing circumstances and maintain sustainability
• How are climate change studies validated?


  To validate evidence related to the climate change debate, studies are peer-reviewed, published in scientific journals, and debated at scientific conferences.