Weather Whys Explains

[00:00:00] While it might not play a role in our day-to-day weather, changes in the Earth’s rotation and orbit around the sun affect our long-term climate. Did you know that the Sahara desert was once a rainforest? Or that Greenland was once regularly ice-free?
[00:00:13] This is the weather-wise podcast. I’m your host ed Oswald. And in this episode, we’re going to explain how that was, and why that will be possible again in the far distant future. Stay tuned. We have a great episode ahead.
[00:00:25] We take the seasons for granted. Winter becomes spring, spring turns to summer, and summer leads to fall. These changes are a result of the Earth’s orbit around the sun, which happens every 365 days.
[00:00:42] But what if I told you the Earth’s orbit isn’t constant? It’s true. Over long timescales, our planet’s orbit and tilt changes. It’s way too small to detect it in a human lifetime, but on geologic timescales, there’s a pattern.
[00:00:55] These patterns are called the Milankovitch cycle Named after Serbian scientist Milutin Milankovitch. He was the first to theorize that the Earth’s orbit on its axis and around the sun changes over time.
[00:01:07] Milankovitch’s findings suggested earth’s orbit changes in one to three ways with progressively longer timescales, wobble, tilt, and orbital shape, or in scientific terms, axial progression, obliquity, and eccentricity.
[00:01:22] The shortest of these it’s axial progression, or our planet’s wobble. Let’s use a spinning top to illustrate this. As it spins, the top wobbles in a circular pattern. Planets do the same thing, just much slower. Our planet takes 26,000 years to complete a rotation.
[00:01:38] The next cycle is obliquity or the amount of tilt that the earth rotates on its axis. over 41,000 years, this tilt varies between 22.1 and 24.5 degrees. This changes the amount of sunlight that the Earth’s surface sees.
[00:01:54] Using the spinning top analogy again, it’s like somebody spun it at an angle. But we’ll have to ditch this analogy for the longest and final cycle, eccentricity.
[00:02:02] Eccentricity is how circular an orbit is, with zero being a perfect circle. Our orbit varies from almost circular to slightly more oval shaped and then back to circular again for a hundred thousand year periods.
[00:02:15] Now that we’ve explained these cycles, let’s put these together in climate terms.
[00:02:19] Planetary wobble affects how extreme the contrast between seasons are. right now, seasons are more extreme in the Southern hemisphere. around 13,000 years from now, the opposite occurs, and seasons become more extreme in the Northern hemisphere.
[00:02:33] The Earth’s tilt may help moderate that, though. When tilt is larger, more sunlight in summer reaches the surface when it’s tilted towards the sun, and less in winter. Right now, the Earth’s tilt is roughly at average science believe the Earth’s tilt is decreasing, however, which will make seasons milder over the next 10,000 years.
[00:02:51] Orbital shape also plays a role in seasonal extremes. Within nearly circular orbit, seasons are generally mild. However, in about a hundred thousand years, the Earth’s orbit will be considerably more elliptical. As a result, the earth receives 23% more sunlight at its closest approach, causing extreme changes between seasons.
[00:03:11] One thing is certain, however: Milankovitch cycles are not the cause of current climate change. Its cycles are too long to explain current changes. However it is a driver of natural change, and one of the reasons why some parts of earth planet change from less rainforests to deserts and a matter of few thousand years, this happens in the Sahara desert. The Earth’s ice ages and their cyclical nature are also thought to be caused by changes in the Earth’s orbit as well. There’s even research supporting the hypothesis that a Milankovitch cycles may have helped human evolution, too.
[00:03:42] However, these cycles are most notable in long-term natural climate change. They seem to explain some, but not all, of these cycles. So, where is the earth headed climatologically over the next one, 10, a hundred thousand years? Scientists have several theories. In general, seasons will moderate overall in the short term, and the planet will continue to warm.
[00:04:04] But this happens on such a long timescale, perhaps tens of thousands of years, that our ecosystem will slowly adapt. That isn’t what’s happening now, where climate change happens in a matter of decades.
[00:04:15] As we move further into the future, the Earth’s tilt will lessen, bringing more sunlight to the poles. The rainforest will move northward as well, bringing deserts to life.
[00:04:25] But at some point tens of thousands of years from now, these trends will be overpowered by a much more elliptical orbit, which may trigger the dawn of a new ice age.
[00:04:33] Luckily humankind has a long time before that becomes possible..
[00:04:37] The Milankovitch Cycles are only a part of our complex climate system. However, understanding how Earth’s rotation and orbit changes with time Allows scientists to better understand our planet’s cyclical climate patterns.
[00:04:50] This was a pretty detail heavy episode, so we have plenty of links in our show notes for you to read further on today’s topic. We’ll certainly return to the subject of climate cycles again in the future, but that’s all the time we have for this episode. We hope you learned something today.
[00:05:05] Weather Whys is a production of The Weather Station Experts and the Weather Whys company. Today’s episode was produced by Derek Oswald and myself from our studios here in West Lawn Pennsylvania. If you’d like to learn more about Weather Whys, visit our website at weatherwhys that’s w H Y s.show. We’d also love to hear from you. You can email us at [email protected].
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[00:05:27] On our website, you can listen this episode or any past episode. Don’t forget to subscribe to weather-wise wherever you listen to podcasts, you can find those links to apple podcasts, Spotify, iHeartRadio, and more on our homepage. That’s all for today. And as always, stay weather-wise.

[00:00:00] Ed Oswald: “Tornado Alley” has long been associated with tornadoes, with May and June the busiest months. However, Tornado Alley is shifting towards the southeast U. S. and toward population centers. It’s also starting earlier than ever. What’s behind this shift? Hi, I’m Ed Oswald, host of the Weather Whys podcast. We’ll look into this in today’s episode.

[00:00:24] Thanks for joining us. So what is Tornado Alley? The term traditionally refers to an area roughly from South Dakota southward to north central Texas. However, tornadoes are becoming more frequent to the east and north.

[00:00:36] Scientists documented this eastward shift. A 2018 study found that tornado frequency generally decreased over The past four decades across Tornado Alley, while increasing to the east across the Lower Great Lakes, and into the Deep South.

[00:00:49] Northern Illinois University researchers found that supercells, the origin of most tornadoes, will become less frequent across Tornado Alley, and more frequent across the eastern U. S. as the planet warms.

[00:00:59] Others have noted the frequency of tornado outbreaks have shifted dramatically eastward since 1950, and they increasingly occur in clusters, or multiple tornadoes in the same area. Research also suggests tornadoes are now more common in the late winter and early spring, and less common in the late summer and early fall.

[00:01:17] The biggest consequence is a significant increase in damage risk. While people live in Tornado Alley, it’s far less densely populated than areas to the east.

[00:01:26] People used to worry about a tornado in downtown Dallas. These studies suggest downtown Memphis and Nashville are more likely to see one instead . Millions more Americans now live in an area where tornadoes are common.

[00:01:36] Is climate change to blame? Yes, but it’s complicated. Nationwide Doppler radar is a powerful tool for detecting tornadoes, even when there’s no one there to see them. This could be responsible for part of the increase.

[00:01:48] The Southeast U. S. is also far more populated as we mentioned, so tornadoes are easier to detect. Severe weather awareness is higher, and in our social media age, videos provide much faster confirmation of tornadic activity.

[00:02:01] But the increase is too significant to pin on these reasons alone. We can likely pin some of the blame on climate change. But is it natural or man made variability the cause?

[00:02:11] One school of thought suggests the uptick is part of an overall increase in severe weather across the U. S. due to climate change. Models have been forecasting this for years.

[00:02:20] However, others argue the variability may stem from bigger cycles, such as differences in Pacific sea surface temperatures. This could also be shifting Tornado Alley, but we don’t have enough data to make a clear judgment.

[00:02:31] No matter what the reason, is, the data suggests that Tornado Alley is no longer just limited to the Great Plains. It’s more important than ever to stay “weather aware.”

[00:02:39] When a tornado warning is issued, take it seriously. Head to an interior portion of the building or your home. If you hear the tornado approaching, get low and protect your head.

[00:02:49] A weather radio is also invaluable during severe weather. Our favorite is the Midland WR 120 NOAA Emergency Weather Alert Radio . It can receive weather alerts directly from the National Weather Service using SAME technology, which allows the weather radio to display the type of warning even after the broadcast message ends.

[00:03:06] That’s the easiest way to keep yourself safe and is far more dependable than the often incorrect weather app. Tornadoes happen quickly, and getting the warning early gives you time to prepare.

[00:03:15] We’ve included links in our show notes to this weather radio, as well as other reviews, but we hope we’ve given you a better understanding of why tornadoes seem to be more frequent and more destructive.

[00:03:23] Weather Whys is a production of the Weather Station Experts and the Weather Whys Company. Today’s episode was produced by Derek Oswald and myself from our studios here in West Lawn, Pennsylvania. If you’d like to learn more about Weather Whys, please visit our website at Weather Whys, that’s w h y s dot show.

[00:03:41] On our website, you can listen to this episode and any past episodes, and also get in touch with us. We’d love to hear from you. Don’t forget to subscribe to Weather Whys to get the latest episodes as soon as we release them.

[00:03:52] You can find those links to Apple Podcasts, Spotify, iHeartRadio, and more on our website as well. That’s all for today, thanks for listening, and as always, stay weatherwise.