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Chapter 4 The Scientific Consensus on Climate Change: How Do We Know We’re Not Wrong?

Chapter 4 The Scientific Consensus on Climate Change: How Do We Know We’re Not Wrong?. Intro . Almost all climate scientists believe the earth’s climate is heating up and human activity is a major cause Majority of Americans still think scientists are divided on the issue

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Chapter 4 The Scientific Consensus on Climate Change: How Do We Know We’re Not Wrong?

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  1. Chapter 4The Scientific Consensus on Climate Change: How Do We Know We’re Not Wrong?

  2. Intro • Almost all climate scientists believe the earth’s climate is heating up and human activity is a major cause • Majority of Americans still think scientists are divided on the issue • How do we know the scientific consensus isn’t wrong?

  3. The Scientific Consensus on Climate Change • Scientific info usually hard to access/ understand • Not in this case, because of political importance • Intergovernmental Panel on Climate Change (IPCC)- four assessments • Very likely warming is due to increase in greenhouse gas concentration • Existing knowledge

  4. American Meteorological Society, American Geophysical Union, American Association for the Advancement of Science– similar statements • Downplay dissenting opinions? • Growth of science, growth of tools to manage info • Database of the Institute for Scientific Information • Figure 4.1- Page 71 • Do you feel that scientific information on climate change is accessible to you?

  5. 1) Scientific Consensus- climate is changing, not solely because natural variability • 2) continued debate- rate of future change- evolution, “tempo and mode” • 3) what kind of dissent still exists? • How fast and in what manner do you think climate change will proceed?

  6. Dissenting Opinions • Media attention to dissenters is disproportional • Most contrarians are not climate scientists • Materials not scientific • “Modeling Climatic Effects of Anthropogenic Carbon Dioxide Emissions”- issue: how well models can predict the futures • Disagreement= details of climate change

  7. Where and what type of unprofessional dissent have you heard? • Do you think the media does a good job or a poor job in informing the public on climate change? • How well do you think models can predict the future?

  8. Why does the public have the impression of disagreement among scientists? • 1)ambiguity between science and politics • 2)prediction- uncertain • 3)failure of scientists to explain arguments and evidence beyond expert community • Little training in: communicating to broad audience and in defending work against well-financed contrarians • “politicizing” the science • If scientists became more involved in political issues concerning climate change would that discredit their work?

  9. Contrarians • American Enterprise Institute, George Marshall Institute • Media Attention • Novelist Michael Crichton • ExxonMobil advertisements • Why do you think these institutions publicly denounce the scientific consensus? • Is climate science too uncertain to warrant action?

  10. How do scientist know that they are not wrong about their assumptions on climate change? • The question is not whether the assumptions might be mistaken but rather is there any reason to think that they are mistaken. • Unfortunately, there is no scientific method or model to prove if they are mistaken or not so we have to wait, only time can tell how the climate will be altered due to anthropogenic effects and natural . • Do you as observers and learners believe that the scientist are mistaken?

  11. The inductive and deductive models of science and how they help • Inductive reasoning • Scientist have taken temperature records from the past 150 years and overall they have shown a gradual increase in temperature since the industrial revolution. • The more recent data show a strong increase in temperature over the last few decades, just as the amount of greenhouse gases have increased. • Deductive reasoning • Scientist develop hypotheses and test them and try to determine whether their consequences, or deductions, are correct. If they are, they support the hypothesis. • Which method of reasoning do you think is more efficient?

  12. Falsifications and what they mean… • IgnazSemmelweis’ theory • Just because Semmelweis made a prediction and it came true, didn’t necessarily prove that his hypothesis that patients were dying due to cadaveric material true. Thus, this lead Karl Popper to suggest that you can never prove a theory true but you can prove it false, which is the view known as falsification. • Falsifications problems. • Since by the time the models would prove what we needed to know the data may be of no use anymore. Thus, many models are tested by seeing if they can accurately reproduce past events. • Is testing models by seeing if they can reproduce past events a good method in determining whether or not a model is accurate?

  13. Climate models are complex because they involve many variables. • Thus, scientist use a technique called model calibration. • Models are viewed as heuristic devices: a means to explore what-if scenarios. • Ensembles

  14. Over ninety thousand participants have produced tens of thousands of runs of a general circulation model. The results in black are the mass participation runs and the results in red are from professional climate scientist. • The many runs showed one general idea which is the earth is warming, we just don’t know how fast the warming is occurring. • However, there is the possibility that all the models are wrong. If the basic model conceptualization was wrong then it’s possible that all the model runs would be wrong. • Do you think that having people go online and run climate models on their home computers is accurate and efficient?

  15. Consilience of Evidence and what it means… • Consilience of evidence. • Scientist tend to look for independent lines of evidence that hold together to support their conclusions. • Climate scientists have been able to develop a consilience of evidence. • Of course, temperatures vary naturally but the global temperatures of the late 20th century have been higher than any temperatures in the previous one thousand years. • Do you think that consilience of evidence is a valid means for drawing accurate conclusions?

  16. Inference to the best explanation… • Since trying to develop an account of why and how scientific knowledge is reliable some philosophers have concluded that the purpose of science is not proof but explanation. • Although best can be biased or vague, the best explanation is the one that matches the criterion of what is in question the best based on models, predictions, and research. • One could believe that the increase in CO2 and increase in temperature were coincidental. However, research and models point to a casual connection between the two and we have no good reason to believe that increases in both are coincidental. • Humans have changed the chemistry of the atmosphere, causing ice to melt, temperatures to increase, and sea levels to rise, and there is no reason to think otherwise. • The question is do you think that humans have impacted the chemistry of the atmosphere?

  17. http://www.youtube.com/watch?v=LmuNPDBbDyE http://www.youtube.com/watch?v=Lf4C1Bwsyj0&feature=related http://www.youtube.com/watch?v=VHzPzLS7Ppc http://www.youtube.com/watch?v=XhExwgiSxt8&feature=related

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