Instructions: Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.
Input: proper question: How much are CO2 levels expected to increase over the next 100 years?
disfluent question: Where umm rather how much are CO2 levels expected to increase over the next 100 years?
context: The executive summary of the WG I Summary for Policymakers report says they are certain that emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases, resulting on average in an additional warming of the Earth's surface. They calculate with confidence that CO2 has been responsible for over half the enhanced greenhouse effect. They predict that under a business as usual (BAU) scenario, global mean temperature will increase by about 0.3 C per decade during the [21st] century. They judge that global mean surface air temperature has increased by 0.3 to 0.6 C over the last 100 years, broadly consistent with prediction of climate models, but also of the same magnitude as natural climate variability. The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more.
Output:
None