Friday, December 29, 2017

Climate Change versus Weather

The Orange one came out today to say that the cold weather shows that climate change is a myth.

Well, that is just dumb.

Here is how it breaks down.

If it is 70 degrees today, and 65 tomorrow, that is weather.

If there is a 30% chance of rain on Tuesday, that is weather.

If there is a 21% chance of rain on any random day in June, that is climate.

If the January temperatures average about 14 degrees, that is climate.

If the January temperatures in the last thirty years have averaged 5 degrees warmer than the average of the previous century, that is climate change.

If the whole world is showing an increase of temperature over the last thirty years that is anomalous when compared to the global averages of the previous century, that is GLOBAL climate change.

"But Jeffy, if the world is warming how can we still have cold days?"

Because the day to day variations are weather.

"But why have we been having these horrible cold spells, isn't that something that shouldn't happen if the world is warming?"

Actually, we have always been having nasty cold spells, tis the nature of the world.  But to better answer your question we have to go into some physics.

As you increase the total amount of energy in the atmosphere (by increasing the global average temperature) you also increase the available energy for storm systems to use to propel themselves, develop themselves, and maintain themselves.  Just because the global average is warmer does not mean that as a side effect you are also going to produce very strong high pressure systems full of arctic air that get pulled down into the United States by a very powerful jet stream and then left in place as the jet wraps around the system, instead of overriding it.

"So you are saying that as a side effect of global warming you can also have occasional colder weather?"

Yep.

It will not be warmer every day, but the AVERAGE of all of the days will end up being higher.

"But how do you know how this works?  What makes you so special?"

Because I went to school, and got a degree in the sciences, and as a side effect one of the super awesome upper division electives was a class in global climate change, taught by the people who actually do these studies.