Issues in Interdisciplinarity 2018-19/Evidence in Climate Change
Case study: Glaciers retreat in the Andes
Climate change has had many impacts on the outlines of our glaciers today, like in the Andes or in the Himalaya where ice land has been retreating over the last few decades .
The Quelccaya Ice Cap (QIC) in the Andes, Perù, faces major changes in its amount of ice. Studies claim that minor changes in climate change are importantly linked to the changes in the ice cap’s mass balance . The landscape of the QIC dramatically changed since 1978 (Fig. 1)  : qualitative evidence is here proof of the changes in geography. This retreat is due to an important rise of the Freezing Level Hight (FLH), which has approximately increased of 160m the past six decades , this increase due itself to global warming in the Andes  Quantitative evidence such as air temperature records on land (Ta)  can also support these variations. With the help of specific data methods, experiments have measured Ta at the QIC summit. These studies have measured a Ta warming rate of 0.14 °C/decade over the periods 1979–2016 in the area . These Ta anomalies have an influence on the FLH fluctuations of the QIC which triggers the loss of ice mass in the QIC. Global warming again has effects on the geographical frame of the Andes. 
Hence, as glaciers retreat, populations experience a shortfall in water supply. In response to that, more expenses have to be provided to reply to agricultural and living needs. For instance, the Rio Orientales project in Perù is based on implanting a water tunnel and bring water from other further sources to reply to water needs in response to the glaciers retreat: these economic changes support the existence of climate change.
The example of glaciers retreat in the Andes illustrate that diverse types of evidence in different fields can support the existence of climate change.
Introduction to evidence
Evidence in geography
Because geography is the science that predominantly portrays our world through images, evidence holds a very delicate important role. Representing the spheric earth on a flat surface, thus creating a map is an ongoing challenge that begun centuries ago. Reading a map must be enlightened by reason and critical thinking because the map is also an effective instrument for creating representations which then evolve with history. For instance, the chosen projection alters the appearance of the map: distortions of distance, direction and scale, which question the importance of evidence in representing the world. Because there is so much evidence, thanks to satellites, and because maps are difficult to create, choices must be made. Indeed, the mapmaker may use different evidence than another maker as the map is the product of his choices. Two types of evidence exist in geography : evidence from qualitative research and evidence from quantitative research. Qualitative evidence informs geography with the support of observations, opinions and unnumbered evidence. Quantitative evidence is informed by numbers, surveys and statistical information.
Evidence in Economics
In Economics - which can be seen as a counter-discipline to Geography -, the question of how reliable theories are, and whether the evidence that is used to establish these, is reliable, raises. Economics is described as either a social science or a natural science, however in the social sciences, evidence is often acquired through anecdotal evidence or testimonial evidence which are rather subjective, hence the findings may be considered as less reliable by one. If economics is seen as a natural science, scientific evidence is being used to make assumptions. One issue that arises in economics is that often the evidence that exists does correspond with the theory behind it, per contra a further link between evidence and real life is difficult to establish.
Evidence in Climate Change
Cultural differences in the acquisition of evidence
In economics, different international viewpoints are considered and discussed when examining and evaluating the impacts of climate change - e.g. at the G20 summit where international political leaders debate about the impacts of climate change -, hence evidence can be interpreted and appraised differently across cultures; working together on the worldwide issue is essential. Cultural differences influencing evidence also appear in the natural sciences; one study carried out by Luncz, investigating behaviour of Chimpanzees across cultures, emphasises the existence of varying evidence across cultures thus the various approaches towards elucidation of evidence. Referring this to the real world, cultural differences lead to differences in evidence, which suggest different approaches towards policy making in the scientific study of economics.
Economics of Climate Change
Climate Change reveals differing approaches to evidence from various disciplines. According to economists, climate change is an outcome of greenhouse-gas emissions leading to negative externalities of production hence creating costs that are not paid for by those who generate the emanations. The Kyoto Protocol (1997), aimed at reducing greenhouse gas emission and soon received feedback that it would harm economic growth. In 1997 Connaughton argues that the protocol would reduce output by up to $400billion in 2010, which is close to the calculations of the EIA from 2008 expecting a decrease in GDP by $397billion billion. It appears that over a time period of 11 years, researchers were able to interpret data similarly; concluding the same. The scientific study of economics may therefore be considered as reliable hence truthful, as evidence shows that even when acquiring it at different times, the outcome is interchangeable.
Geography in climate change
Largely caused by humans in the burning of fossil fuels, climate change has many impacts on the outline of our world today, modifying our landscapes. Because geography is a wide and resourceful discipline with sub-disciplines, its implication in the understanding of climate change is crucial. Geography indeed offers new understandings of the issue, varying from perceiving spatial dimensions of climate change to grasping the urban changes of global warming. Generating global warming, climate change covers transformations like rising seas and melting ice as well as extreme weather events which have consequences on the geographic world. Climatology (itself classified within physical geography) addresses the issue through its focus on dynamic and statistical climatology. Geography also aids in understanding the possible effects of climate change on environmental systems and societies. K. O’Brien and R. Leichenko suggest that there are winners and losers of climate change. These winners and losers are divided regarding their geographical position: winners ‘will include the middle- and high- latitude regions, whereas losers will include marginal lands in Africa and countries with low-lying coastal zones’, hence showing how geography adds to the economic study of climate change and offers different perspectives.
Economics and geography work hand in hand in order to understand climate change. Geography, with its sub-disciplines, brings the basis of the scientific work in order to fully grasp the issue while economics focuses on its impacts and future and how it is apprehended by society. Various types of evidence used by both disciplines aid in the global understanding of climate change. Both disciplines are crucial in order to comprehend the issue and be able to live with it, and, to a certain extent fight it.
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