In the era of fake news, misinformation tends to spread quickly – especially during a time of crisis. The deceptions that have sprung up in the wake of hurricanes Harvey and Irma show that it's high time to separate fact from fiction.

When Harvey hit landfall, a picture of a shark allegedly on a highway in Houston went viral, fooling at least one reporter. The same fake picture, which has been around for years, cropped up during Irma. Yet before stopping to check if the picture is real, people retweet or share it on Facebook hundreds of thousands of times.

The same is true for blaming man-made climate change for Harvey and Irma. Before actually analyzing the data, one news outlet wrote, "Harvey is what climate change looks like." Another called the one-two punch of Harvey and Irma the potential "new normal." Other environmental activists went as far as to say that the two natural disasters are reason to finally jail officials who "reject science."

There's only one small problem with such accusations. Man-made warming did not cause Harvey and Irma. As carbon dioxide and other greenhouse gas emissions have increased, there have been no trends in global tropical cycle landfalls. Before Harvey and Irma, with a little bit of luck, the United States was in a 12-year hurricane drought. More importantly, the average number of hurricanes per decade reaching landfall in the U.S. has fallen over the past 160 years.

This comes not via "denier data," but from mainstream science. The Intergovernmental Panel on Climate Change reported in its most recent scientific assessment that "(n)o robust trends in annual numbers of tropical storms, hurricanes, and major hurricanes ... have been identified over the past 100 years in the North Atlantic basin," and that there are "no significant observed trends in global tropical cyclone frequency."

According to the National Oceanic Atmospheric Administration, "It is premature to conclude that human activities – and particularly greenhouse gas emissions that cause global warming – have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity."

Other media outlets took a more measured approach, claiming that man did not cause Harvey and Irma but supercharged them. The reasoning is that warmer sea surface temperatures increase moisture in the air and, in turn, up the intensity of the hurricanes.

But University of Washington climatologist Cliff Mass, after examining precipitation levels in the Gulf, discredited this claim. He found that "(t)here is no evidence that global warming is influencing Texas coastal precipitation in the long term and little evidence that warmer than normal temperatures had any real impact on the precipitation intensity from this storm."

CNN asked Bill Read, former director of the National Hurricane Center, whether man-made climate change was intensifying storms. He said no, adding, "This is not an uncommon occurrence to see storms grow and intensify rapidly in the western Gulf of Mexico. That's as long as we've been tracking them that has occurred."

Even if man-made warming were responsible for Harvey and Irma, the policies that tax or regulate carbon dioxide and other greenhouse gas emissions are costly non-solutions. The U.S. could slap a $40 tax on all carbon dioxide emissions, and the "climate benefits" would be hardly noticeable. By the year 2100, the averted warming would be less than two-tenths of a degree Celsius, and the averted sea level rise would be less than 2 centimeters.

The costs, however, would be staggering. Because carbon dioxide-emitting conventional fuels meet 80 percent of America's energy needs, the tax would harm families multiple times over as energy is a necessary component for almost everything we make and do. Between now and 2035, the country would experience an average employment shortfall of 400,000 lost jobs, a total loss of income exceeding $20,000 for a family of four, and a $2.5 trillion hit to the overall economy. That means less wealth to combat future challenges, whether they are climate-related or not.

Political opportunism is distracting from what is important: helping the people in Houston, Florida and the islands. Policymakers should focus on improving natural disaster response, resilience and preparedness. Blaming man-made climate change on Harvey and Irma is truly denying the data.