During the last 15 years, the Earths surface temperature rose at a rate of 0.04°C a decade, far slower than the 0.18℃ increase in the 1990s. Meanwhile, emissions of carbon dioxide rose【C1】______This pause in warming has raised【C2】______in the public mind about climate change. A few skeptics say that global warming has stopped. Others argue scientists understanding of the climate is so flawed that their judgments cannot be【C3】______with any confidence. A convincing explanation of the pause therefore【C4】______both to a proper understanding of the climate and to the【C5】______of climate science. As evidence piled up that temperatures were not rising much, some scientists【C6】______it as a pause. The temperature had fallen for much longer periods twice in the past century or so,【C7】______the general trend was up. Variability is part of the climate system and a 15-year【C8】______was not worth getting excited about. An【C9】______way of looking at the pauses significance was to say there had been a slowdown. Most records dont include measurements from the Arctic, which has been wanning faster than anywhere else. Using satellite data to【C10】______the missing Arctic numbers, scientists put the overall rate of global warming at 0.12℃ a decade. A study by NASA puts the 'Arctic【C11】______' over the same period【C12】______lower, at 0.07°C a decade, but that is still not【C13】______. It is also worth remembering that average warming is not the only【C14】______of climate change. According to a study, the number of hot days, the number of extremely hot days and the【C15】______of warm periods all【C16】______during the pause. A more stable average temperature hides wider extremes. Still, attempts to【C17】______that stable average have not been convincing, partly because of the conflict between【C18】______temperatures and rising CO2 emissions, and partly because observed temperatures are now falling【C19】______the range climate models predict. The models embody the state of climate knowledge. If they are wrong, the knowledge is probably【C20】______too. Hence, scientists still attempt hard to interpret the pause. 【C1】