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Posted at 11:00 AM ET, 04/13/2010

Atmosphere's revenge? Monarchs in short supply

Butterflies battered by Mother Nature

* Cool showers, then warm-up: Full Forecast | Radar: Weather Wall *

I've written previously on the Butterfly Effect, wherein the proverbial flapping of a butterfly's wings over, say, Mexico, might start a chain reaction of events in the atmosphere eventually impacting the weather at a later time over, say, Washington, D.C. The flapping wings, at least symbolically, represent the small uncertainties (errors) in the initial conditions fed into forecast models, which grow chaotically (unpredictably) as models predict further and further into the future, thereby limiting the temporal range of useful weather predictions.

Perhaps, as suggested (mostly in jest), real butterflies are more to blame for forecast busts than the oft standard cry: "The models blew it." Even if this were true, it's not likely to apply this spring. Normally this time of year, millions of real-life monarch butterflies are migrating from their winter haunts in Mexico toward the northern U.S. and Canada. This year, however, it seems the atmosphere has taken revenge by devastating the butterflies' winter sanctuary in the mountains of Mexico.

During the normally dry and warm month of February, up to 15 inches of precipitation battered the monarchs' habitats with heavy rain, snow, sleet and freezing rain (likely related to El Nino). Estimates are that up to half the monarch population perished (see here and here).

Moreover, monarchs were already in decline due to deforestation and loss of food supply (milkweed) in the U.S. and Mexico, thus limiting the number of butterflies returning to Mexico in the fall. Not incidentally, it will likely be harder this fall than in past falls for those inspired by Ann Posegate's previous post (on monarch life cycle, annual migrations and sightings) to spot monarchs passing through the area.

So, will the monarch shortage mean more reliable forecasts by computer weather models? Don't count on it. Even if the impact of flapping butterfly wings on model predictability were assumed more literal than symbolic, there would remain many more and significant sources of initial condition errors (uncertainties), which forever will limit the accuracy and range of weather predictions.

On the other hand, even if the near impossibility of monarchs actually contributing noticeably to forecast error could be demonstrated, I for one would wish no harm to these beautiful creatures. Hopefully their populations will make a comeback. To this end, Mark Taylor, director of Monarch Watch at the University of Kansas, is urging people to plant milkweed across the country, especially in the southern U.S., as a "lifeline" for the butterflies during their exhausting migration.

By  |  11:00 AM ET, 04/13/2010

Categories:  Nature, Nature

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