Mother Nature Network: Statistically speaking, global temperatures have risen more slowly over the past 15 years than in the decades prior, leading some to proclaim incorrectly that we are experiencing a "hiatus" in global warming, or even that climate change is not real. But two new studies illustrate that global warming remains a problem and that human activities are the source. The most recent study, published on Nov. 10 in the journal Nature Geoscience, examines the historic effect of ozone-depleting gases such...