The short answer would have to be "no." If you check out today's New York Times weather map you will see a simple explanation for this weather. On one side of the continent the jet stream has dipped way south, providing the West with unusual coolness and rain, even into Phoenix. Meanwhile, the pattern of the jet stream in the midwest and east coast is experiencing the "flipside" of the circulation coin, traveling far to our north.
So, simply put, the flow dynamics of the jet stream, while unusual, are immediately responsible for this weather.
Another part of the story...in Boston we boast that the month of March lasts here for ninety days. What do we mean by that? Again the simple answer is that the Atlantic Ocean, a huge body of water that takes relatively long to warm up in the spring, is right at our front door. Ocean breezes come inland through June, taking even the warmest days down into the 50s. Why isn't that happening now? Simply because the southwesterly flow of air, which is linked to the flow of the Jet Stream, is strong enough to keep an onshore breeze from occurring. The result? We stay warm.
A third part of the story is explained by our weather last week. A "back door cold front" bathed the city in cool ocean air carried on a breeze from the northeast. This wasn't a nor'easter because there was no precipitation involved with it. It was simply part of the dynamic of an air current circulating around a high pressure area to our north and east. The weather last week was more like San Francisco than Boston, consistently cool, oceany, and never warming up even in full sunlight.
So, it all these patterns point to a "no" for global warming, why do scientists insist that the phenomenon is real?
For an answer to this question all you have to do is go to the superb "Earth Observatory" sponsored by NASA. All kinds of interactive maps will show you that there have been long-term warming trends, not necessarily on land, not necessarily in the temperate zones where most people would notice it, but in the Arctic Ocean and waters adjacent to it.
Scientists have demonstrated without question that the planet is warming by using simple methods of observation. That doesn't mean we notice it on a day to day basis. Certainly if we compare last winter's notable cold and abundant precipitation with this year's winter, we see a big difference. But that is not the evidence for global warming.
Global warming and global climate change are planet-wide phenomena that are measured not day to day, but over decades, and not in a single locality like Boston, but all over the Earth, including our oceans.
Enjoy the nice weather but think hard about how your own activities can calm the trend to global warming. Walk, ride a bike, or take public transportation instead of driving. Turn down the heat and skip the AC. Eat less meat. Try to travel less by air.
I couldn't help but think Global Warming was the culprit until I read this. It's interesting to put it in perspective. While we are experiencing incredible summer-like weather in March, at home in California over break I was cold! It was in the low 50's and rainy! I guess that would be an argument against Global Warming. No matter the cause, I definitely am grateful, seeing as last winter Boston had snow on April 1st! Clearly, we cannot count Global Warming out, but it is something we must understand is not happening over night.
ReplyDeleteSorry you experienced that cold weather back home! We understand now that global phenomena like climate change are not necessarily observable in the short term (one season to the next).
DeleteThanks for your note Cara!
ReplyDeleteGood point. I think we need to look at the "bigger picture," for example the data on the NASA site.
ReplyDeleteRight. There are lots of potential consequences of global warming. At the beginning of the semester we talked about the importance of predicting. With the data scientists are collecting, we are better able to predict the outcomes of global warming.
ReplyDeleteI think it is very important for students to realize that climate change does not happen overnight, and in fact it is the little things adding up (like turning down our AC while a window is open...) that contribute to global warming. Thanks for the insightful information!
ReplyDeleteYou're welcome! Thanks for your note!
DeleteYes the jet stream often "flips" as you say and the result is unusual weather. This is one of the short-term weather patterns and not overall climate. (-:
ReplyDeleteI agree with most of the posts above on that I also assumed that a mild winter and an earlier start to summer was due to global warming! Hearing about the weather in the West Coast being colder for the past few days than it has been here on the East Coast made me wonder how quickly global warming was affecting us. After reading your observations, I understood how this is not due to global warming, and was kind of shocked! But I'm glad I now have a better understanding of why we have this sudden warm weather (which is beautiful and no ones complaining). Although like you said this is just a short term weather pattern and not our overall climate, we should enjoy it while it lasts!
ReplyDeleteI totally agree. Let's enjoy this great weather. We do need to look at our patterns of consumption, travel, energy use, etc. in order to make decisions about how we can ameliorate global warming.
DeleteGreat. Now you have an argument you can use too! (-:
ReplyDeleteI was in northern California for Spring break and joked that the weather on the east and west coast had switched, now I know that that's actually what's happening! Very interesting and relevant post.
ReplyDeleteThanks for your note!
DeleteThanks fir your note. Yes, there is plenty of evidence that the mean temperature of the planet is going up, as we studied using maps from NASA.
ReplyDeleteI think once we see sea levels rising (due in part to melting of the Greenland ice cap) it won't seem so gradual.
ReplyDeleteI thought it was really interesting how the flow of the jet stream can affect the warm weather we have been having. Initially, I thought it definitely had to do with global warming. Its interesting though how we as humans don't think twice about the warm weather and just enjoy it instead of thinking how strange this is and what it means for our planet.
ReplyDeleteWell the anomalies in the jet stream don't affect things in the long run...they are part of daily weather patterns rather than climate.
DeleteSo Kevin do you think that the evidence on the NASA site is not persuasive?
ReplyDeleteThank you for sharing this! I found this really helpful because I thought the weather changes were 100% due to global warming. I'm from Florida, so last year's winter was horrible for me and I was not prepared for this winter to be so warm, especially not as warm as it has been this week.
ReplyDeleteYou are welcome. Have people in Florida been trying to lower carbon emissions by 1) using solar power and 2) cutting down on the amount of AC used?
DeleteIt's funny that you sent us this article now, because over break, we in Palo Alto had an unusual amount of rain, and the "unusual coolness" you write about. Someone said to me back home, "I heard this rain is all coming from Alaska!" and I didn't quite understand what she meant... but now I see the influence of the jetstream across the continent.
ReplyDeleteI personally think that whenever we comment about this weather and attribute it to global warming, especially in a somewhat flippant or joking manner, it all seemingly lessens the magnitude of the issue. If discussions about global warming take place in a scientifically inaccurate fashion, doesn't that give "ammo" to the politicians/activists/skeptics in general who already firmly believe that we have no idea what we're talking about and that global warming is bogus?
-Gunita Singh
So we need to understand that global warming is a long-term phenomenon that is observable in ways that are different from how weather is observable. For example, anomalous sea temps in the arctic over decades.
DeleteThe NASA website provides incontrovertible evidence of global warming and we only need to look at some of those maps to refute skeptics, etc.
For me, teaching science is about helping students interpret the real world around them. Of course this is open to interpretation and creative thinking but there are certain bottom-line facts that speak for themselves. Global climate change is one of them.
The rain was coming from Alaska in a way!
I was surprised to see how much carbon dioxide I added to the environment by flying. It absolutely outweighed all my conservation efforts, including never ever using a car, barely ever eating meat, never using AC, keeping my house cold in winter, etc.
ReplyDeleteYou're welcome.
ReplyDeleteThe reasons for changes in the jet stream are complex. But partly they have to do with "bulges" of cold air that form in the arctic. This season the cold air "bulged" southward over Europe and Asia, causing the jet stream to flow north of us. This is not the only reason but a major one.
As far as conservation I was shocked to see how much carbon dioxide is added to the atmosphere by flying. One flight to the west coast totally outweighed all my conservation efforts all year including only riding a bike and never taking a car, keeping my house super cool, never ever using AC, hardly ever eating meat, etc. So it points to the fact that just by living "normal" lifestyles we are really adding a lot to global warming.
You can show this piece to your roommate and see if it makes sense to her as a person who I assume is not taking a science course.
ReplyDeleteI think in your country most people are not contributing significantly to global warming because they just don't use the resources we do here. But a single airplane trip home definitely adds an enormous amt of carbon dioxide to the atmosphere.
My very limited plane travel totally outweighs all the conservation I do---no AC, no car, cold house in winter, barely ever eating meat. So, just by living "normal" North American lifestyles we ad a huge amount of carbon dioxide to the environment.
RIGHT ON!!!
ReplyDeleteHi Mandy. The jet stream is based on a number of factors like the rotation of the Earth and temperature differences between various parts of the globe. It is kind of like the ocean conveyer belt but it is a lot more changeable and it takes a much shorter time to circle the globe (days instead of years). One of the things that affects it are "bulges" of cold air that head south from the North Pole. They are called "Arctic Outbreaks." This year, the cold air bulged southward into Europe and Asia causing very cold temps there and relatively warm temps here in North America.
ReplyDeleteI think that experiencing severe changes in weather, and knowing that Boston weather is notorious for changing almost overnight, prevents us from seeing the bigger picture of climate change. It makes it feel as though it isn't really happening when we as individuals only observe it in such a small window of time. But we have to remember that, as you mentioned, looking at the larger trends across the globe over hundreds of years can tell us more than a single week in one specific city.
ReplyDeleteYou make an excellent point. How do you think we can get your idea across to people, since by nature humans are kind of short-sighted?
DeleteI think that it is really interesting to note that jet streams are the causes of this recent warm weather. Although jet streams are discussed on weather segments, I feel that it is pretty natural for people to blame global warming for the unusual shifts in weather. In regards to the weather, I personally find myself thinking that experiences of warm weather during cold months are due to the phenomena of global warming. However, it is important to keep in mind of other aspects of weather that directly influences temperature. Likewise, it’s essential for people to note that global warming should be a total consideration of weather changes happening over the decades and worldwide. A random change of weather in one particular place for a limited period of time shouldn’t force us to think that global warming is truly at the forefront.
ReplyDeleteWell global warming is in the "forefront" if you consider long-term climate change and other dangers like rising sea levels (caused by ice melting at the poles and from glaciers elsewhere). It's also important to keep in mind that the great ocean conveyer belt can be altered because of decreased salinity in northern latitudes (because of so much melting ice). All of these factors are threatening the long-term sustainability of our ecosystems.
DeleteSo just because this warm spell is not an indication of global warming that doesn't mean that global warming is not real. (-:
This is so interesting that it's not global warming. It makes me wonder if this drastic weather change will effect the summer and even next winter?
ReplyDeleteThat's an interesting question. The National Weather Service issues long-range forecasts that might be address your concern.
Deletehttp://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/t.gif
You claim that this is merely a weather event so therefore can't be global warming. But as you say climate is measured over decades. It is the aggregate of weather over long periods of time. More warm events more often means that our globe is warmer. Climate is nothing more than the aggregate of weather. You cannot say that this warm weather is caused by global warming but instead you should say that this event adds to proof that the globe is warming. We are stuck in a reverse mindset of cause effect.
ReplyDeleteAlso, you should pay close attention to the arctic. A larger number of days without ice cover means that high pressure systems will develop (sea absorbs sun ice reflects) and alter jet streams across the northern hemisphere. I suggest reading Dr. Jeff Masters at the weather underground. He is one of the few people who elucidates the connection between weather and climate.
Thanks for your note. Your point on ice cover is super important and I teach exactly what you refer to. All of these things contribute to global warming/climate change. And of course, climate changes as a result of aggregate weather patterns over long periods of time.
DeleteOne of the things I've been stressing with my students is that we have to look deeper at scientific evidence in order to understand global warming. If someone claims that the warm weather in Boston this week = global warming it is just as logical to say that the cool weather in the West "disproves" global warming.
That's why I focused so much this semester on discussing anomalous trends in the Northern Ocean. But it took this unusually hot weather to bring on a "teachable moment."
This was a very interesting article. Like many others, I would too jump to conclusion that the warm weather we are experiencing in Boston is due to global warming. However, after reading this it opened my eyes to what may be really occurring and how global warming is a long term phenomenon rather than a short and sudden change in weather like we are experiencing.
ReplyDeleteBrittany Sebade
The jet stream shift is temporary but global warming is increasing. The only thing is that this is not a sign of it.
ReplyDeleteThanks for your note. At the beginning of the semester we studied some maps published by NASA that show a warming trend in the Northern Ocean. That warming trend happens to be the most significant long-range sign of global warming. And it provides rock-hard evidence that warming is occurring at the global level. However, we can't attribute this warm spring to global warming. Why not? One reason is that previous years in the 1920s and 1940s were much warmer in Boston. This was before much global warming had occurred.
ReplyDeleteBoston (like most temperate, terrestrial environments) is changeable in regard to weather. So we can't take short-term phenomena at this small geographical perspective to explain global changes in climate.
One thing you are right about---scientists predict that anomalous weather changes will become more frequent and more severe as the climate changes. So we can expect more heavy rain, more frequent drought, and more major changes in temperature as the climate continues to change.
It really is weird to me how our planet works. I am not from the north so coming to Boston last year and experiencing the blisteringly cold winter was incredibly difficult. So when this year came around I was dreading another experience like that but now it seems hotter outside than it is back home. I'm glad to hear that it is not directly related to global warming, but it is worrying to me that weather patterns can change so drastically so quickly.
ReplyDeleteProfessor, if you had not introduced this blog to the class I would have continued to blame this change in weather on global warming! So interesting! I love the winter and wish we had a bit more of it this year though!
ReplyDelete-Cibelle Levi
Sorry for such late comment but I believe that the constant unstable increase and decreased of temperature in Boston throughout this week is quite interesting. Ranging from the extreme warm temperature around mid 70s to low 80s, it is definitely quite relieving to hear that it is not a cause of global warming. If Jet streams are the main cause for the increase of climate temperatures, will it do any harm in the long run? This is what I am do not know and concern about....
ReplyDelete-Lena Wang
Wow! Global warning isn't to blame? I have been raised to curse the folks who don't recycle (and obviously I still think everyone should recycle and take care of the earth), but this makes me question everything I know, or think I know. It does make sense, though, that jet streams are the cause of the warm winter. I still believe that global warming is a serious issue, but now I will stop and think before I blame everything on the phenomenon. This is a very interesting blog that should make everyone stop and think about the causes of climate change.
ReplyDeleteLast year my rhetoric professor gave us an article about the minority of scientists who don't believe in global warming (or at least don't fully agree). The article explained how these scientists were ostracized by their peers and how science was experiencing a 'tyranny of the majority' moment. Although I do believe in global warming, this article has convinced me that there are more factors involved in the global crisis then we like to think.
ReplyDelete