One look at the data indicates that the skeptics’ view is wishful thinking, at best. It is true that if you look at the period 1998-2013, there is very little warming. But that is because 1998 was an extreme outlier — a sharp spike on the graph. That year was much warmer than the preceding or subsequent few years.
If you plot global temperatures over a longer time period, covering 50 or 100 years, you get a line that jiggles up and down but generally trends upward at an alarming slope. Look closely and you’ll notice that 2005 and 2010 were both a bit warmer than 1998.
Why is this happening? Because “the atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years,” according to the executive summary of the 2,000-plus-page IPCC report.
By processes well-known to science and reproducible in the laboratory, these gases trap solar heat. Since the Industrial Revolution, when humans began burning fossil fuels on a vast scale, the concentration of carbon dioxide in the atmosphere has increased by an astounding 40 percent. Unless all the physics textbooks are wrong, this causes warming.