Guest essay by Eric Worrall

LSE Grantham Institute Communications Director Bob Ward has written a post for the Guardian in which he admits he’s not sure of how anthropogenic CO2 might be impacting hurricanes, but he thinks President Trump should answer for them anyway.

Irma and Harvey lay the costs of climate change denial at Trump’s door

The president’s dismissal of scientific research is doing nothing to protect the livelihoods of ordinary Americans

Bob Ward
Sunday 10 September 2017 09.05 AEST

As the US comes to terms with its second major weather disaster within a month, an important question is whether the devastation caused by hurricanes Harveyand Irma will convince Donald Trump and his administration of the reality of climate change.

The president’s luxurious Mar-a-Lago estate in Florida may escape Irma’s wrath, but with the deaths of so many Americans, and billions of dollars in damage to homes and businesses, the costs of climate change denial are beginning to pile up at the door of the White House.

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Climate change cannot be blamed for the hurricane count in any single season, nor for the occurrence of any single storm, but there are three ways in which it is making the consequences worse.

First, although the intensity of a hurricane depends on many factors, warmer seawater tends to promote stronger storms. Average sea surface temperatures have been rising, and some parts of the North Atlantic and Gulf of Mexico are warmer than average at the moment, which is a key reason why both Harvey and Irma became so strong so quickly.

Second, a warmer atmosphere can hold more water vapour, which can result in heavier rainfall. That is true not only for hurricanes but also for weaker storms across the world. Even relatively mild tropical storms can cause great damage by dropping huge volumes of rain over one area.

Third, apart from strong winds and heavy rainfall, hurricanes cause damage through storm surges as their winds push seawater ahead of them. Storm surges can inundate extensive low-lying coastal areas, sweeping away everything in their path. Sea levels have been gradually rising globally, making storm surges bigger and deadlier.

Scientists are still not sure about the other ways in which climate change may be impacting hurricanes. The main reason Harvey created such extreme flooding around Houston was that it stalled over the city and dumped rain for several days without moving on. We do not know if climate change played a role in creating the atmospheric conditions that made that happen.

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Bob Ward

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The biggest problem for alarmists like Bob is there is no upward trend in hurricane frequency or intensity.

As I noted in a previous post, NOAA doesn’t think the alleged impact of anthropogenic CO2 on storm intensity is detectable. (h/t Benny Peiser)

… 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. That said, human activities may have already caused changes that are not yet detectable due to the small magnitude of the changes or observational limitations, or are not yet confidently modeled (e.g., aerosol effects on regional climate). …

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Here is what the IPCC says about climate change and hurricanes;

… Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century … No robust trends in annual numbers of tropical storms, hurricanes and major hurricanes counts have been identified over the past 100 years in the North Atlantic basin … In summary, confidence in large scale changes in the intensity of extreme extratropical cyclones since 1900 is low …

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Speculative climate models suggest there should be an upward trend. But that predicted projected upward trend has not been observed in the real world.

Many climate alarmists seem to think we should treat climate model projections as equivalent to real world observations. For example, climate scientist Kevin Trenberth said the following back in April this year;

… With climate models as tools, we can carry out “what-if” experiments. What if the carbon dioxide in the atmosphere had not increased due to human activities? What if we keep burning fossil fuels and putting more CO2 into the atmosphere? If the climate changes as projected, then what would the impacts be on agriculture and society? If those things happened, then what strategies might there be for coping with the changes?

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The models are not perfect and involve approximations. But because of their complexity and sophistication, they are so much better than any “back-of-the envelope” guesses, and the shortcomings and limitations are known.

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The reality is climate models ARE computer driven guesses. Climate models have never been validated in any meaningful scientific sense – an issue which bothers some climate scientists so much, they argue that the definition of science itself must be changed, to accommodate climate models’ lack of scientific falsifiability.

… Climate models are important and complex tools for understanding the climate system. Are climate models falsifiable? Are they science? A test of falsifiability requires a model test or climate observation that shows global warming caused by increased human-produced greenhouse gases is untrue. It is difficult to propose a test of climate models in advance that is falsifiable.

Science is complicated – and doesn’t always fit the simplified version we learn as children. …

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I believe it is past time people who attempt to promote computerised guesses as established fact are held to account for their nonsense. The scientific method, falsifiability, is what separates science from superstition. Scaremongering, attempting to lay blame on President Trump for natural disasters on the basis of unproven climate model projections, projections which have no corroboration from real world observations, in my opinion is beneath contempt.