The passages given below are followed by a set of questions. Choose the most…

The passages given below are followed by a set of questions. Choose the most appropriate answer to each question

Global climate change pundits have for long been blowing heat and cold over melting ice caps, rising ocean levels and unusually hot summers on the one hand and receding deserts, shrinking biodiversity and colder winters on the other. Climatologists are, however, unanimous in their opinion that regional variation notwithstanding, the earth as a whole is becoming warmer - and largely due to increased human activity. And yet, as a continent Antarctica would seem to be bucking the trend. Recent reports quoting American scientists from the south pole say that while temperatures in every other continent have risen over the past century, Antarctica has become appreciably colder over the past 35 years and continues to cool, becoming the only one of Earth's seven continents to react differently to global warming. The world's average temperature over the last 100 years has risen by 0.06c a decade and the average actually went up to 0.19c between 1979 and 1998. In the Antarctic, on the other hand, temperatures fell on an average by 0.7c a decade. Traditional theories of climate change have held that the effects of global warming ought to be magnified at the poles.

Nonetheless, recent research points out that while the Arctic is indeed getting warmer, the Antarctic is definitely getting cooler. This will mean that previous estimates of rising sea levels that included the melting ice caps of both the north and south poles will have to be suitably revised. So what is the mystery behind the cooling of the white continent? Since most of the inhabited and industrialized countries are clustered close to the Arctic, polluting emissions waft across to the north pole, creating a greenhouse effect, warming the air and loosening the ice sheets. The complex interplay of ocean currents appears to have changed temperatures cooling the southern ocean around the Antarctic and transforming the pole’s temperature profile. Antarctica’s harsh desert valleys are turning cooler, setting off a series of ecological consequences in the region. Meanwhile, here's another contradiction: reports from new Zealand describe how there is a surfeit of global warming-induced break-away icebergs in the southern hemisphere.

According to the passage, the most important factor for global warming is