Science-based policy is shrinking ozone hole

Posted on October 21, 2024 by WeatherGuys Editor

The Southern Hemispheric ozone hole usually begins to develop in mid- to late August, as the hemisphere emerges from its winter, and peaks in mid-October.

The Antarctic ozone hole — the total area where ozone amounts are below 220 Dobson units — on September 21, 2023, the day of its largest extent for the year. The annual maximum extent of the ozone hole in 2023 (light purple bar, measured in millions of square kilometers) compared to all years in the satellite record (dark bars). NOAA Climate.gov image based on NOAA (map) and NASA (graph) satellite data. (Image credit: NOAA)

This year it first appeared closer to the end of August and by mid-September was 18.48 million square kilometers in size, smaller than in recent years, including both 2022 and 2023. Though this year’s slow start does not necessarily reflect a recovery of the ozone layer, it does support the notion that expert guidance has made a positive contribution to this vexing problem.

Just a few years after the ozone hole was detected via satellite, the industrialized nations of the world, meeting in Montreal in 1987, adopted what is known as the Montreal Protocol. That international agreement, based upon the consensus scientific understanding of the problem, placed prudent restrictions on the use of chlorofluorocarbons, or CFCs.

The result of this scientifically informed policy-making has been a gradual but systematic healing of the ozone hole. Despite the success of the Montreal Protocol, current estimates are it will require another four decades, if the protocol is followed, before recovery toward pre-ozone hole conditions.

This success should serve as a leading example of the power of scientific analysis and understanding to shape important environmental policy.

The world is facing a slower-burning crisis as a result of human-induced changes to the atmosphere that are, in turn, compelling a change to a warmer climate. There is no lack of scientific consensus of the roots of this problem nor any shortage of science-based prescriptions for seeking its remedy.

The time has long passed for our society to seriously debate, and then begin to take, the bold actions necessary to meet this crisis. Our scientific and industrial infrastructure is more than sufficient to meet this pressing challenge — we have successfully done so before!

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: History, Phenomena

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Can we control the weather?

Posted on October 14, 2024 by WeatherGuys Editor

We watched in stunned horror the suffering of our fellow citizens across parts of the South in the aftermath of the nearly back-to-back disasters wrought by hurricanes Helene and Milton.

Naturally the question of whether these storms were made more intense and impactful by the ongoing, slow background warming has been considered in discussions of these events.

It is true that the Gulf of Mexico sea surface temperatures in the regions from which these storms came is as many as 4 degrees Fahrenheit warmer than normal this season. It is also true that the ocean heat content, a measure of how much heat is actually available in the ocean, well below the surface, has been increasing during the warming era. Both of these ingredients are potent fuel for tropical storm intensification.

So, from that perspective, it is reasonable to conclude that global warming has at least a plausible physical connection to the development of these monsters.

(Image credit: Environmental Change and Security Program, Woodrow Wilson International Center for Scholars)

One of our major political parties has decided that it is best to ignore this possible connection and to carry on as if nothing of concern were happening. One particular elected public servant, U.S. Rep. Marjorie Taylor Greene, has even suggested that there is a nefarious conspiracy afoot wherein unspecified government officials are controlling the weather. Writing on X on Oct. 3, she proclaimed, “Yes, they can control the weather. It’s ridiculous for anyone to lie and say it can’t be done.”

Any expert, and certainly the two of us, can say with great certainty that it is not possible to control the weather. Even the huge investments in cloud seeding in the 1950s and 1960s, made in hopes of alleviating local drought, were eventually declared inconclusive — certainly not a triumph for weather control.

It might be better if the passion exhibited by Taylor Greene, along with other elected (and unelected) officials in her party, was directed toward continued funding for better understanding of the science underlying the weather and climate rather than asserting outrageous conspiracy theories and threatening to weaken our exceptional National Weather Service.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: Climate, Weather Dangers

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Is it safe to shower or bathe during a thunderstorm?

Posted on October 10, 2024 by WeatherGuys Editor

Taking a shower or bath during a thunderstorm could put you at risk from a lightning strike. When you are indoors during a thunderstorm, the National Weather Service (NWS) recommends that you seek a safe location, away from electrical systems, electronic equipment, and avoid plumbing, including sinks, baths and faucets. Most indoor lightning casualties are due to conduction via lightning. The plumbing systems in many households include metal pipes, which can serve as conduits during lightning strikes. Lightning travels long distances in metal including wires and pipes. Metal does not attract lightning, rather it provides a path for the lightning to follow.  Water is also excellent conductor of electricity.

National Weather Service’s poster for Lightning Awareness Week (Image credit: NOAA/NWS)

The plumbing systems in many households include metal pipes, which can serve as conduits during lightning strikes. Lightning travels long distances in metal including wires and pipes. Metal does not attract lightning, rather it provides a path for the lightning to follow.  Water is also excellent conductor of electricity.

Lightning strikes the United States about 25 million times a year. Lightning kills about 20 people in the United States each year, and hundreds more are severely injured. If caught outdoors, never shelter under an isolated tree. When lightning strikes a tree, or other object, energy travels down the object and outward along the ground surface. This is referred to as the ground current and causes the most lightning deaths and injuries. A lightning bolt that strikes a tree can cause the tree sap to boil and burst shards of the tree outward.

Just because a lightning bolt is a few miles away doesn’t mean that you are safe. Most lightning starts inside a thunderstorm and travels through the cloud. A “bolt from the blue” is a lightning bolt that starts inside a cloud, then travels away from the cloud before going to ground. That bolt can strike the ground at a location that is blue sky above.

When thunderstorms are in your area, no outside place is safe. So, follow the advice “When thunder roars, go indoors.”

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc. edu or jemarti1@wisc.edu.

Category: Severe Weather, Weather Dangers

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Do weather radars detect more than precipitation?

Posted on September 30, 2024 by WeatherGuys Editor
Scientists can distinguish rainy weather as seen to the west and north in graphic from flocks of birds because they appear as circles or blobs on radar screens. Most migratory birds take off from daytime resting and refueling habitats at sunset for their nightly journey. (Image credit: National Center for Atmospheric Research)

Yes. Radar, an acronym for RAdio Detection And Ranging, consists of a transmitter and a receiver. The transmitter emits radio wave pulses outward in a circular pattern.  Objects scatter these radio waves, sending some energy back to the transmitting point where it is detected by the radar’s receiver. The intensity of this received signal indicates the size and density of the suspended objects, such as precipitation. The time it takes for the radio wave to leave the radar and return indicates the distance.

Radar is designed to detect precipitation intensity and type, but it can detect living things as well. Flying insects in huge numbers can reflect enough energy back to a radar site to be detected. As an example, mayflies emerge in summer in enormous numbers around the Mississippi River between Wisconsin and Minnesota and are often detected by the weather radar in La Crosse, WI.

Some bird species gather at large communal roosting sites, particularly during their migration. The birds can be seen on radar as a flock takes off in the early morning. The flock appears on radar as an expanding, fading ring until they either fly above or below the radar beam and are no longer detected. Their signature often appears on radar during the morning departure, but not in the evening when they return. This is because atmospheric conditions affect the radar beam path. The beam is bent slightly downward in early morning due to a temperature inversion that often develops in the lower atmosphere. This departure in the path allows the radar to detect objects at lower altitudes more easily. During the evening, temperature inversions are weaker or non-existent and the beam bending doesn’t occur, inhibiting detection.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc. edu or jemarti1@wisc.edu.

Category: Phenomena, Seasons

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What is “The Old Farmer’s Almanac” forecast for winter?

Posted on September 23, 2024 by WeatherGuys Editor

“The Old Farmer’s Almanac” recently published its 2024-25 winter forecast. For the Upper Midwest region, it predicts winter will not be as cold as usual. The precipitation and snowfall forecast are for below average.

NOAA’s Seasonal Temperature Outlook for Dec-Jan-Feb 2024-2025, showing the effects of La Niña (Image credit: NOAA/Climate Prediction Center)

But don’t count on that forecast, as there is no proven skill. “The Old Farmer’s Almanac” does not share how it makes its forecast, so it cannot be judged scientifically. “The Old Farmer’s Almanac” also makes a weather forecast for specific time periods in a given season. Such detailed forecasts can be announced but are not trustworthy scientifically.

Seasonal weather forecasting is a science challenge. The National Oceanic and Atmospheric Administration’s Climate Prediction Center also makes seasonal forecasts. It explains the underlying principles of its forecast and provides validation of the forecasts publicly (see https://www.cpc.ncep.noaa.gov/products/predictions/long_range).

These modern day seasonal forecasts rely on known relationships between climate and some key forcing mechanisms, such as the El Niño. An El Niño is a periodic warming of the equatorial Pacific Ocean between South America and the international date line. This warming is a natural variation of the ocean and is used to predict departures from average conditions rather than to make specific weather forecasts. For example, a year with a strong El Niño leads to less snowfall than average in Wisconsin. These seasonal forecasts also take into account the climatic impacts of other global oscillations uncovered by the research of atmospheric scientists.

El Niño Southern Oscillation-neutral conditions are present, as equatorial sea surface temperatures are near to below average in the central and eastern Pacific Ocean. A La Niña watch is in effect, as La Niña is favored to emerge in September-November (71% chance) and is expected to persist through January-March 2025. Wisconsin winters tend to have more precipitation and near-average temperatures during a typical La Niña.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc. edu or jemarti1@wisc.edu.

Category: Climate, History, Seasons

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