By Paul Homewood

 This is the sort of drivel that passes for science these days:

Ask people to name the world’s largest river, and most will probably guess that it’s the Amazon, the Nile or the Mississippi. In fact, some of Earth’s largest rivers are in the sky – and they can produce powerful storms, like the one now soaking California.

Atmospheric rivers are long, narrow bands of moisture in the atmosphere that extend from the tropics to higher latitudes. These rivers in the sky can transport 15 times the volume of the Mississippi River. When that moisture reaches the coast and moves inland, it rises over the mountains, generating rain and snowfall and sometimes causing extreme flooding.

 Atmospheric rivers are an important water source for the U.S. West. NOAA

In the past 20 years, as observation networks have improved, scientists have learned more about these important weather phenomena. Atmospheric rivers occur globally, affecting the west coasts of the world’s major land masses, including Portugal, Western Europe, Chile and South Africa. So-called “Pineapple Express” storms that carry moisture from Hawaii to the U.S. West Coast are just one of their many flavors.

My research combines economics and atmospheric science to measure damage from severe weather events. Recently I led a team of researchers from Scripps Institution of Oceanography and the Army Corps of Engineers in the first systematic analysis of damages from atmospheric rivers due to extreme flooding. We found that while many of these events are benign, the largest of them cause most of the flooding damage in the western U.S. And atmospheric rivers are predicted to grow longer, wetter and wider in a warming climate.

The article goes on to great lengths to tell us the bleedin obvious- that heavy rain can cause flooding. And then ends up claiming not only that heavier rain will occur in future, but also that this is already happening, without the slightest evidence being offered:

A moister atmosphere means worse storms

Our most significant finding was an exponential relationship between the intensity of atmospheric rivers and the flood damages they caused. Each increase in the scale from 1 to 5 was associated with a 10-fold increase in damages.

Several recent studies have modelled how atmospheric rivers will change in the coming decades. The mechanism is simple: Greenhouse gases trap heat in the atmosphere, warming the planet. This causes more water to evaporate from oceans and lakes, and increased moisture in the air makes storm systems grow stronger.

Like hurricanes, atmospheric rivers are projected to grow longer, wider and wetter in a warming climate. Our finding that damages increase exponentially with intensity suggests that even modest increases in atmospheric river intensity could lead to significantly larger economic impacts.

I believe that improving atmospheric forecasting systems should be a priority for adapting to a changing climate. Better understanding of atmospheric rivers’ intensity, duration and landfall locations can provide valuable information to residents and emergency responders.

It also is important to discourage new construction in high-risk areas and help people move to safer locations after major disasters, rather than rebuilding in place.

Finally, our study underlines the need to reduce global greenhouse gas emissions. These storms will keep coming, and they’re getting stronger. In my view, stabilizing the global climate system is the only long-term way to minimize economic damage and risk to vulnerable communities.

Particular reference is made to atmospheric river events in and around Sonoma County near San Francisco. So let’s check what CLIMOD2 has to say about winter rainfall trends there.

There is clearly little trend in total winter rainfall, which can vary considerably year on year. Four of the five wettest winters were in the 19thC:

As for the maximum daily rainfall each year, the tops were 1866/67, 1981/82, 1995/96 and 1861/62. Again there is no evidence to support the article’s assertion:

The author, Tom Corringham, a Postdoctoral Scholar in Climate, Atmospheric Science and Physical Oceanography, admits that his research is confined to economics and atmospheric science. Consequently his work is at best theoretical, and should not be used to make unsubstantiated claims about what is actually happening.


February 2, 2021 at 05:36AM