Spring features a drought in Texas, the late-starting tornado season in Oklahoma, and dwindling ice roads in Siberia and Canada. But first, let’s talk about an underappreciated feature of the Earth: Its magnetic field. Let’s go Around The World — and beyond.
Magnetic Field Shields Earth From Deadly Bombardment Of Solar Wind
We’re not alone. No, I’m not talking about extraterrestrial life. That question remains unresolved. But Earth is not alone in having an atmosphere.
Venus has one; Jupiter has one; the sun has one. And, significantly, Mars and the moon do not.
Let’s start with the atmosphere of the sun, which looks placid from 93 million miles away, but which is anything but calm when viewed close-up. Inside, the sun is a furnace fueled by the conversion of hydrogen to helium, with an ever-so-slight loss of mass.
By the famous mass-energy conversion formula, E=mc2 (blame it on Einstein), that tiny loss of mass equates to a whole lot of energy (the speed of light — c in the equation — is an enormous number and then it’s squared). The sun also boils on its surface, sending a constant stream of particles outward (the solar wind), and occasionally exploding with an outburst of radiation and particles. It’s like a person breathing normally who suddenly sneezes. And, as the exhalation of a sneeze can contain dangerous pathogens, so the exhalation of the sun can contain lethal radiation and ionized molecules that can damage the cells of Earthbound animals.
The sun is a spinning ball of gas (it completes a rotation in about 24 days) with a magnetic field that is caused by electrical currents in the interior. This magnetic field reverses every eleven years and is responsible for the sunspot cycle. Magnetic storms at the sun’s surface are associated with massive outbursts of charged particles and radiation.
The Earth, similarly, spins on its axis (once a day) and has a magnetic field caused by the sloshing of liquid iron deep in its bowels. Lucky for us, because the magnetic field traps the incoming blasts from the sun and shields us from their harmful effects. Without this protection, cellular life would be bombarded with mutation-causing ions and radiation.
Like the magnetic field of the sun, that of the Earth reverses every so often — but not nearly as often as the sun’s. There is now conclusive evidence that the Earth’s magnetic field has switched poles many times in the past; the most recent reversal was about 780,000 years ago. There is some evidence that it is preparing to reverse sometime in the relatively near future.
Of interest to humanity is the evidence that when the Earth’s magnetic field is preparing to reverse, its strength diminishes by a factor of ten.
If this happens, not only will humanity be threatened, but the atmosphere itself will be in peril of being blown away. Just like the atmosphere of Mars once was.
Mars is believed (the evidence is compelling) to have had an atmosphere in the past. The red planet is also known to have had a magnetic field; its molten iron interior sloshed like that of the Earth. But Mars cooled and the interior solidified, cutting off the electrical currents that cause planetary magnetic fields. Then the solar wind literally blew the atmosphere away.
Let’s hear it for Earth’s magnetic field.
Drought In The Southwest US
The drought in California, though still severe, has improved this winter. However, a large area from Arizona to Oklahoma and Texas is experiencing extreme to exceptional drought. Wildfires have burned pastureland, so that volunteers needed to bring hay to the stricken areas to save livestock from starvation. As an example of the extreme conditions in the affected area, as of April 17, Amarillo, Texas had received rain on only one day since mid-October.
According to the National Weather Service’s 3-month forecast for May-June-July, rainfall is likely to return to normal over the drought area, and afternoon thunderstorms could ease, but not erase, the precipitation deficit.
Late Start To Tornado Season
Tornado frequency normally ramps up in Oklahoma in the spring. This year, the tornado season is getting its latest start ever. No tornadoes have been reported in the state through the first four months of 2018. The latest previous first tornado was on April 26.
The lack of tornadoes in Oklahoma, and the drought in the area, have the same meteorological cause: A farther-south-than-usual track of the jet stream, which shunted Gulf of Mexico moisture eastward. A dry and stable flow from the west has dominated the area.
The persistence of this weather pattern is consistent with the climate change expected from global warming.
Ice Roads In The Arctic
Last year, the New York Times ran an article that included anecdotal evidence that Canadian ice roads, used in winter to supply fuel and goods to isolated communities which otherwise could only be reached by air, are open for a shorter season as the arctic warms. This year, the Times featured an article about ice roads in Siberia, where drivers complain that the roads close a month earlier than they used to, and a truck occasionally crashes through the dwindling ice in an attempt to make one more lucrative run.
Though no one has made a scientific study of the ice roads, there is no reason not to believe what the drivers report. It is consistent with the conclusive evidence that the arctic is warming at several times the rate of the rest of the planet.
There will be more about arctic warming in the mid-May Climate Change Checkup.
The next Weather Around The World will be published on June 5, 2018