Friday, August 15, 2014

Kinky jet streams

The latest manifestation of climate change is the phenomenon of kinky jet streams.  Two problems are caused when a jet stream gets its kink on—extreme weather is seen in places where it is very rare and, weather patterns move along more slowly.  Last winter, a major jet-stream kink brought record drought to California while sucking down seriously cold Canadian air to the USA south.  The slowing of weather patterns means that instead of getting a 1.5" rain, there are 6", 12", and more flash flooding downpours.  These have become so common, they barely rate mention any longer except for those poor souls who discover they live on a 500-year floodplain.  The latest big rain dropped over 13" on Long Island.

Here, Jeff Masters explains kinky jet streams better than I. And as usual, the transcript is below the read more link.





JESSICA DESVARIEUX, TRNN PRODUCER: Welcome to The Real News Network. I'm Jessica Desvarieux in Baltimore. And welcome to part two of our conversation about climate change with our guest, Jeff Masters. Jeff is a meteorologist and the director of meteorology for the website .

Thanks for joining us, Jeff.

JEFF MASTERS, DIRECTOR OF METEOROLOGY, WUNDERGROUND.COM: You're welcome.

DESVARIEUX: Thanks for joining us from Ann Arbor, Michigan, I should say also.

So, Jeff, let's pick it up from where we left off. We were talking about climate change. And I want to specifically talk about the international climate change summit that's supposed to take place in Paris next year. Its goal--I want to ask you: what is the specific goal? And give us a sense of the people that are going to be represented at this summit.

MASTERS: It's a hugely important meeting. About only once every six years do all the nations of the world get together to negotiate a binding climate agreement, which means that we have to have every nation commit to targets to reduce their greenhouse emissions. And the target that we're looking for is to reduce greenhouse gas emissions by about 70 percent by the year 2050, because that's the level that's deemed necessary to avoid a 2 degree centigrade warming of the climate by the end of the century compared to preindustrial levels. Now, that's a tall order, because we've already warmed the climate by about 0.85 degrees centigrade, which means we've only got about 1.15 degrees centigrade left. We're almost halfway to the maximum we can do.

DESVARIEUX: Yeah. And as you said, it sounds like a tall order. What specific policies would have to be in force in order to get these emissions reduced that much?

MASTERS: Yeah, the number one is we've got to reduce the burning of coal. That's the dirtiest fuel we have out there for generating carbon dioxide. We also need to reduce burning of oil and natural gas and quit deforesting our rain forest, because that's another big source of emissions to the atmosphere.

DESVARIEUX: So is this binding at all? I mean, if you violate any of--let's say nations come together and they agree on this. But who's going to really enforce it?

MASTERS: Yeah. I mean, there will be penalties. There'll be monetary penalties if you don't meet your targets. That's what's meant by a binding agreement.

DESVARIEUX: Okay. So is there going to be an international body that's going to enforce this? I'm just curious.

MASTERS: Yeah, there will be an international body that watches over the treaty. I mean, there was something in force like this for the Kyoto Protocol back in 1997.

DESVARIEUX: Okay. And I understand, too, Jeff, that you just recently wrote an article--or I should say you're currently in the process of writing an article for  on the jet stream. Can you talk about what exactly you're putting together?

MASTERS: Yeah. I was talking about the jet stream, which is that upper-level river of air that tends to control our weather. And the reason it controls our weather is because it acts as the boundary between cold air to the polar side and then warmer subtropical air on the other side. And normally the jet stream flows straight,West to East over our latitudes, which means you don't have a big sort of variation in the weather patterns. But when that jet stream starts to take these big bows, these big excursions like a meandering river, that's when we tend to get really major extreme weather events.

In particular, this past winter over the Eastern U.S. and Midwest, this so-called polar vortex episode happened. And what that was: it was a big bulge in the jet stream. It went way far to the south, allowing cold air to spill out of Canada, down much farther south than usual. And on the converse side, over in California you have a compensating ridge, kind of a /əˈji/ shaped bulge in the jet stream going far to the north, which allowed very warm air from Mexico in the south to bring California its warmest and driest winter on record. So when you get one of these major jet stream undulations, it tends to bring extreme weather of both kinds, both the hot extreme and the cold extreme, and wet and dry extremes.

And there's evidence that these sorts of unusual jet stream undulations are increasing in frequency. In fact, they've doubled over the past 11 years compared to the previous 22 years. So that's a big concern. And we don't even know what's causing this jet stream behavior, but it makes sense that something to do with climate change might be involved. When you put the level of heat and moisture into the atmosphere that we've done over the past few decades, something has to give. Weather patterns have to shift. And one of the culprits we're looking at right now is the fact that the sea ice in the Arctic is about a factor of 2 less than it was 40 years ago, and that could be affecting global weather patterns and the jet stream.

DESVARIEUX: Alright. Thank you so much for joining us.

Jeff Masters joining us from Ann Arbor, Michigan.

Thank you so much for being with us.

MASTERS: Alright. You're welcome, Jessica.

DESVARIEUX: And thank you for joining us on The Real News Network. more

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