Part of this post appeared on the original blog under the name “A Natural Complexity” in 2012.
A new El Niño is beginning, apparently.
Earlier this month, NOAA (National Oceanic and Atmospheric Administration) announced that while the ENSO is currently still neutral, the Pacific is warming in ways that suggest an El Niñowill develop sometime this year. When it will develop or how severe it will be if it does, they cannot say yet. NOAA reassesses the ENSO every month, and they should be much more sure of their prediction in June.
ENSO extremes cause extreme weather of various types, so if an El Niño does develop, we can expect this coming winter to bring unseasonably warm weather to parts of Alaska and Canada and a lot of snow and rain to the Southeastern United States. Some Americans will therefore announce that global warming is definitely happening because of all the weird weather, others will announce that global warming can’t be happening because look at all this snow, while still others will insist that it is just El Niño, which has recurred for thousands of years and has nothing to do with greenhouse gases. Little sub-arguments will rage over whether and how global warming and the ENSO interact (nobody actually knows). The great debate will rage; is this weather natural?
And that is the wrong question.
The truth is that global weather patterns are extremely complicated and any particular weather event has many different causes, all operating together. Identifying what caused any particular hot day is a bit like attributing a wave in a crowded swimming pool to one particular swimming kid. The occasional cannon ball leap aside, the question cannot be answered. Scientists don’t try.
What scientists do instead is to look at probabilities. They look at the swimming pool and they measure the waves and they analyze the measurements with powerful computers. They ask “is this group of waves about what we would expect, given that a dozen kids are hopping up and down in the water?” If the answer is no, they don’t need to know which wave is natural and which wave isn’t; they know the pattern as a whole has changed and there is something new happening in the water.
When climate scientists announced that the heat waves and droughts of 2012 were definitely the result of global warming, they did not mean that natural weather has ended, or that we will never have an unseasonably cold spell again (we’ve have some since then). What the scientists meant was that the pattern has changed. There is an extra kid in the pool, now. And every wave, big and small, will now be the combined result of all the original kids plus the new one.
This winter, we’re going to be swimming around next to a very bouncy kid, the Boy, El Niño. He’s been in the pool a long time. He’s one of the older kids, though he isn’t always splashing around so much. But even though the Boy might be drawing attention to himself, each wave will still be the result of many causes all interacting together, and the new global warming kid will still be in the pool, making the entire pool different than it would be if he were not there.
The new kid in the old pool is us.
Categories: Climate Science, Extreme Weather | Tags: climate predictions, reposts, science explainer | Permalink.
About three weeks ago now, researchers announced that the melting of a group of glaciers in Antarctica had become “unstoppable.” The water in those glaciers, once released, will raise sea levels by about three feet over the next few decades or centuries, drowning some low-lying coastal regions and islands and exposing many more to an increased risk of flooding from storm surges. The announcement made the news and now seems to have disappeared.
Aside from protesting this back-to-business attitude (did you all hear this? The shape of the continents as we know them is about to change!), I want to clear up some possible misconceptions.
First of all, the reason scientists are sounding the alarm about this one group of glaciers is that these are the glaciers they looked at. Antarctica is a very big place and research there is difficult, so there are a lot of glaciers they did not look at so closely but that might be melting also. Plus, there are other sources of meltwater (like the glaciers in Greenland) raising sea levels and as the oceans get warmer they expand, also raising sea level. So we’re not really looking at just three feet of rise over the next two hundred years, we’re talking about three feet from this one source, plus more feet from all of the other sources.
Second, not all of this melting is visible to a casual glance. Glaciers can and do melt by getting shorter; you can visit a place and say “OMG, that glacier used to fill this valley and now it stops all the way up there!” But they also get thinner. A glacier can lose a lot of mass and still cover the same area that way. The only way to tell is to measure the changing elevation of the surface, which these scientists did using the ERS-1 satellite.
With these particular glaciers there is also another problem. Glaciers form on land and flow over land, but they do not automatically melt or break up on contact with the sea. If the water is cold enough, they just keep going for a while, forming large floating shelves of ice. But these glaciers are so thick and heavy that they need very deep water in order to float. Until they get out to deep water, they keep flowing along the ground, even though the ground itself is below sea level. The place where a glacier finally separates from the ground and begins to float is called the grounding line and the location of the grounding line is another thing that can change dramatically without the glacier looking much different from a casual glance. If a glacier gets thinner it also gets lighter and needs less water to float. The grounding line retreats inland.
Where the grounding line is matters a lot, matters more, actually, than whether the ice actually melts.
The issue is that flouting ice does exactly the same thing to sea level that extra water does. You can demonstrate this yourself with a glass of water and some ice cubes. Drop the ice in the water and the water level rises–it may overflow the glass. But notice that if the water level is right at the top of the glass (as if it has just overflowed), the ice floating in the water actually sticks up above the top of the glass a little. So what happens if you let that ice melt, does the glass overflow again? No.
The space ice takes up in water is exactly the same as the space it will take up when it melts. Ice floats because water expands when it freezes (water is at its most dense just shy of 40°F or 4°C. Warm it or cool it from that point and it gets bigger) and the tip of the iceberg that sticks up out of the water is always the exact difference in volume between the ice and the same water in a liquid state.
What this means is that ice raises the sea level when it floats in the sea, whether it has melted already or not. So when scientists say that the grounding line of a glacier is moving inland by multiple kilometers a year, that is a very big deal.
Finally,there is the issue of what “unstoppable” means. Does it mean it is time to give up hope, that there is nothing we can do anymore? No, it does not.
First of all, glaciers flow, so how soon a glacier ends up in the sea depends not just on how quickly it melts but also on how free of obstruction its path is. So if the end of a glacier melts, the ice that was behind it can flow more freely and it heads toward the sea faster, unless there is a mountain ridge or something like that to get in the way. Part of what the scientists mean by “unstoppable” is that they don’t see any mountain ridges under these particular glaciers they are studying, so with the front of the glacier melting the ice now has an increasingly clear path to the sea.
Now, that really doesn’t sound like he means that drastically cutting emissions wouldn’t stop the melting, only that a drastic reduction isn’t going to happen, in his view.
Let’s prove him wrong on that, shall we?
Categories: Climate Science | Tags: climate predictions, science explainer | Permalink.
I’ll follow up on the bad news about glaciers next week. In the mean time, here is an article on the drought in California that I originally published on the old blog site–since the drought is ongoing and has already spawned some awful wildfires, it seemed timely to revisit the issue. This article was originally published in February, 2014 and has since been edited for greater clarity.
For much of the United States, this winter has been all about cold and snow. But for the other half of the country, though, this winter has been about drought and heat. And it turns out, the two extremes are related.
California is entering its third consecutive year of deep drought. In 2013, California as a whole got less than a third of its average amount of precipitation. January is typically one of the area’s two wettest months, but as of mid-January, some areas had received only a trace of rain. Los Angeles had received no rain at all. This is the driest period on record for California. Tree ring studies suggest that this is the driest the region has been for nearly 500 years. Nevada and Oregon are also in very serious droughts, and parts of eight other states are also in a state of Federal emergency due to drought.
Much of the Western U.S. is also unusually warm. Parts of California topped 80 degrees in January, while parts of Alaska approached 60 degrees. 60 degrees in Alaska in January is not only bizarre but also dangerous, since the warmth has caused a massive avalanche that completely cut off the only road into the town of Valdez. Wherever it occurs, heat makes drought worse by increasing rates of evaporation.
At the beginning of February, the California Water Project, for the first time ever, announced it would not supply any more water until further notice. The move means that the state must now rely only on local water sources, such as wells, without access to regional reserves.
The current drought will probably break eventually, but this sort of thing could be the new normal. Current land and water use policy in the American West is based on the amount of water available in past years, but we now know that the recent past was an unusually wet period for the region. What looks like drought to us may simply be a return to normal. Over the past thousand years or so, this area has also experienced several “mega-droughts,” extra-dry periods lasting a hundred years or more.
If California is heading into a mega-drought, or even just returning to the historical normal, then there won’t be enough water for its people and industries, a shortage that will have national consequences. More wildfires means that California will have to draw on out of state resources more often, potentially depleting the country’s ability to fight fires in other regions. 15% of the food sold in the U.S. in grown in California, the loss of effective irrigation would raise food prices nation-wide.
Does this have anything to do with global warming? In a word, yes.
This winter’s wet cold in the east and the dry warmth in the west are related. A persistent blocking high—a huge bubble of high pressure—has sat over top of the northeast Pacific for months. As the name implies, the blocking high prevents storms carrying moisture from the Pacific from making it to shore. The bubble also diverts the jet stream northward, directing warm, tropical air straight up into the arctic and destabilizing the polar vortex. We’ve gotten used to “polar vortex” being used to mean a cold snap, but actually it refers to a ring of high wind around the poles that usually serves to keep the coldest polar air in place. When the polar vortex weakens, it leaks, spilling frigid air into unusual places, like Atlanta, Georgia. This blocking high has been in place for nearly a year now.
But this process—a weakening of the polar vortex because of melting sea ice—was predicted by climate scientists years ago. It’s exactly what they said would happen. So, yeah, this is what climate change looks like.
So, let’s DO something about it, please?
It has been a strange week for weather.
A massive rainstorm has flooded historic Harper’s Ferry, West Virginia, not an unprecedented event, but still dramatic. At the same time, drought-struck California has begun what may be its worst wildfire season in recorded history. Perhaps even more disturbing, widespread flooding in the Balkans has caused multiple landslides, inundated whole villages, and the still-rising water now threatens Serbia’s most important power plant. At one point, a third of Bosnia was under water. The most frightening detail is that some of the flooded and destabilized areas were active mine fields left over from the Bosnian war, and now nobody knows for sure where those mines are.
Whether these floods and droughts would have happened without global warming is debatable; the Balkan floods especially are unusual, the worst in 120 years, since record-keeping in the region began, but unusual whether has always happened occasionally. As a general rule, of course, larger and more frequent flood events, with correspondingly drier periods in other places or between floods, are par for our course now in many parts of the world.
What is unambiguously a result of climate change is the recent bad news about the Antarctic.
There has been a lot of confusion about ice in Antarctica, in part because some of the ice there has actually been growing in recent years. But the part of the ice that really matters has been shrinking and the bad news is it’s shrinking twice as fast now as it was only a few years ago.
To clear up the confusion, the big distinction for Antarctic ice is between sea ice and glacial ice. Glaciers begin their existence as snow that falls on land. If more snow falls in the winter than can melt, the snow builds up and eventually is crushed into ice by its own weight. Because of that weight, glaciers flow gradually towards the sea, like giant frozen rivers. Glaciers store the snow of thousands of years. That is a lot of water. If a glacier melts or flows into the sea faster than new snow can replenish it, that water comes out of storage and the sea level rises.
In contrast, sea ice forms when the sea freezes. The extent of sea ice matters for all sorts of reasons, but sea level rise isn’t one of them. That is because floating ice takes up exactly the same amount of room in the water as the meltwater from the ice would. That is why you can make your drink overflow by dropping ice into it, but when you let the ice sit and melt the level of your drink does not change at all. Try it sometime. What matters for sea level is not whether water is liquid or solid but whether it is in the sea already or not.
Antarctica’s expanding sea ice does not negate global warming because, unlike the arctic sea ice, it mostly melts during the summer already. When we talk about the northern ice cap shrinking, we’re talking about its size over the summer. Summers are getting warm enough now, even in the arctic, to melt a lot of it. But most of Antarctica’s sea ice already melts away during the summer, so when we talk about its changing size we are talking about it in the winter, and Antarctica’s winters are nowhere near warm enough to melt ice. Its increasing sea ice probably has more to do with changing wind patterns and a less salty ocean (from all the glacial meltwater) than temperature per se.
Another possible source of confusion is that Antarctica has multiple distinct regions of glacial ice and one of its regions actually was growing more ice until recently. The most recent measurements show that region as stable, neither gaining nor shrinking. But most of Antarctica’s glaciers have been shrinking for a while now.
But the bottom line is that recent satellite data shows that the melting of some of Antarctica’s glaciers has sped up dramatically in recent years; the satellite can see the surface of the ice dropping in elevation. This is not a prediction or a model, it is observed data. Researchers are sure now that some of the glaciers of Western Antarctica are going to completely melt. The only major question is how long will they take to do it?
There is enough water in those glaciers to raise global sea level by four feet. All that melting could take two hundred years, but that’s hardly reason to ignore the threat, and of course there are a lot of other glaciers that could melt also, speeding up sea level rise.
The headlines from all of this are mostly that the melting is now “unstoppable,” which obviously implies quite a bit of doom and gloom. But the researchers themselves don’t say that now is the time to throw in the towel; now is the time to get busy. “Unstoppable” doesn’t mean exactly what it seems. I’ll get into more details on that later this week.
For now, the take home message is that there is no time to wait. The water is coming.
Categories: Climate Science, Extreme Weather | Tags: current events, science explainer | Permalink.
You know, sometimes I think the problem is that most of us just don’t count. No, no, no, I don’t mean we don’t count as in we don’t matter, I mean we don’t count as in we look at a number of objects or people and don’t bother to count them.
Like how so many people say “I’m just one person, what does it matter what I do?” Well, how many people is everyone else? Even big shots, political and economic leaders, are one person each. I don’t mean to deny that President Barack Obama has more power than you do, but he is powerful because other just-one-persons do what he tells them to do, not because he is more than one person. Everything that has ever been done by human beings has been done by people who were just one person each, just like you. “One” is the number of people humans come in, and it hasn’t stopped anybody else from making a difference.
Just as there are people apparently unaware that nobody is more than one person, there are also those unaware than none of us are less than one person. All exhortations that you should make a difference are based on the remarkable proposition that you have the option to not make a difference, even though all human beings do make a difference simply be existing. We eat and breathe and talk, we weigh something. Even if your contribution to the world is in no way unique (I’m not sure it’s possible to not be unique, but this is about math, not your self-esteem, and I’m trying to keep things simple), you do matter. Consider all the drops of water in a bucket; sure, each one is just a drop in the bucket, but together they weigh forty pounds, and there isn’t any drop in the bucket that does not add to that weight. Your weight is exactly the same whether you stay in the same bucket as everyone else, or jump to a new bucket with hardly any other drops in it. Whether your weight helps create the status quo or helps shatter it, you make a difference. You can’t avoid making a difference. All you can do is decide what difference you want to make.
Merkel was not an oil man per se. Although his petroleum use was on the high end in those days, as he traveled a lot for business, Jim Merkel was not claiming more responsibility than anyone else, he was just claiming responsibility. He had a sudden, profound awakening, utterly changed his lifestyle, and has devoted the rest of his life to helping others do the same. I recommend his book.
But I recommend following the intent, not the letter, of his advice. He suggests a form of energy diet, a variation of the sort of thing you can find on the Internet if you search for ways to calculate and reduce your ecological footprint. In theory, the idea is to count up how much of the Earth’s resources you use, and then reduce your use until you reach your fair share. In practice, however, measuring your whole footprint is complex to the point of impossible, so you have to make various assumptions and shortcuts, all of which can be debated until the end of the world.
Now, certainly any radical reduction is a good thing, so go ahead and use a foot-print-reduction plan if you want to. You’ll raise your own awareness and that of your friends and associates while you’re at it. But there is a simpler way; get off fossil fuel.
Fossil fuel is the heart of the problem, although land use, cement production, and other factors also contribute to climate change. Part of the issue is that cheap energy exacerbates all of these other problems (would anyone cut down the rainforest to graze cattle for export if shipping were slow and expensive?). The larger part of the problem, though, has to do with the global energy budget. Plants do most of our carbon sequestration and ultimately provide all of our fuel in one form or another (including both feed for draft animals and fossil fuel). There is a direct relationship between how much energy is stored in plant matter and how much carbon dioxide burning or eating those plants releases–because the plants stored the energy in carbon molecules in the first place. Burning fuel always releases carbon dioxide and always will, but if you used energy slowly enough that the plants could re-grow (a sound economic plan), you would be carbon-neutral by definition. This kind of sensible, nearly automatic thriftiness is almost impossible with fossil fuel, because the whole point of using fossil fuel is to get more energy than modern woodlots and farm fields can give us. That, by definition, means releasing more carbon dioxide than the plants of today can sequester. That causes global warming. Limiting ourselves to the energy available in the active, non-fossilized part of the biosphere (which includes solar, water, and wind, but not nuclear energy) will end human-caused global warming, provided we can learn to use our resources sustainably.
Of course, in our society, using fossil fuel is often logistically necessary, but that can be changed—by you. And me, and other people. There’s more than one of us involved. Once we start trying to live without fossil fuel, we can go about solving the problems that we encounter (building local food systems and alternative fuel transportation options, for example). When you run into a wall you can get busy building a ladder. Other people will then climb your ladder.
Categories: Climate Solutions | Tags: climate change solutions, ending global warming, reposts, science explainer | Permalink.
Cowboys and Indians 3 will post on Monday. In the meantime, here is a re-post from the original blog on the Climate Emergency Institute site.
Global climate change may be too abstract a notion for many people to think clearly about. Information, like pizza, cannot be chewed or digested well if you bite off too big a piece at once. Anything that prevents large numbers of people from thinking clearly and concretely about a problem can effectively block public change.
In the interests of moving through this block, I contacted Bill Hulslander, Chief of Resource Management at Assateague Island National Seashore, and asked him about sea level rise. Using his responses, plus my own familiarity with the island as a former intern there, let us look at climate change in one, particular place.
Assateague Island is part of the barrier island chain protecting much of the Atlantic and Gulf coasts. These islands and peninsulas are essentially very large offshore sand bars with forests, shrub-lands, and marshes growing on them. They protect the mainland from the worst of ocean storms and provide valuable wildlife habitat, unless they are converted to resort towns, as most of them have been.
Assateague is one of the few exceptions. It is not one park but three, with different parts of the island managed by different agencies. Famous for its free-roaming horses, Assateague also supports several endangered or threatened plants and animals. The island is 37 miles long, and varies in width from about two miles on the southern end to a few hundred yards in the north. It straddles the border between Maryland and Virginia. As a low-lying island, Assateague is vulnerable to changes in both sea level and the frequency and intensity of storms. As a tourist destination familiar to millions of people, it is a place where people might see change they can relate to.
Not all change on Assateague is related to sea level rise, and not all sea level rise is related to climate change. For example, the land in this part of the country is subsiding for geologic reasons, so the sea would be gaining on the island anyway. Also, Assateague is made of sand and sand moves easily. Storm waves would constantly reshape the island no matter what.
Mr. Hulslander says that the sea has been rising globally since at least the 1800’s (he does not say whether that rise is due to global warming, but it certainly could be, given that the Industrial Revolution had already begun). That means it is impossible to say what the island would do, how it would move, without sea level rise. There is no baseline data. All this means that it is hard to tell which of Assateague’s changes are natural and which are not. It may be enough to know that Assateague is changing, and that climate change is one of the reasons why.
Assateague moves west as major storms wash sand over the island and into the bay behind it. The process erodes the beach while building up the marshes on the other side of the island. Most visitors don’t notice this movement, because it has not changed the overall character of the land in recent years. Park rangers do notice it. They have had to move or abandon some of their infrastructure on the island. They can easily remember old, historic buildings lost to storms, their former locations now permanently under water.
The rangers tell the story of a man whose family did not sell their land on Assateague to the government when the park was created. He returned years later, curious about his property. The rangers gently explained to him that his land (which he had been paying county taxes on) was now several yards off shore. The rangers helped him sort out his tax problem, and the story is usually told in a light-hearted way, but one can imagine this family’s disappointment and regret.
A sea-level rise of 3.5 to 9 inches (8 to 22 cm) by 2040 may claim some of the barrier island’s valuable landscape.…The pace of sea-level rise will be the determining factor in the ability of habitats to adapt to new landscapes and environmental conditions. If the pace is too swift, [and the growth of the marshes cannot keep up] the island may reach a tipping point and become more of a broken chain of low, sandy islands.
The loss of an intact barrier could make the mainland behind more vulnerable to storms, as well as being psychologically difficult for those who love Assateague. Whether or not the island breaks up, many of the natural communities on Assateague may be altered or destroyed due to periodic flooding and changes in groundwater salinity. In the short term, says Mr. Hulslander, some endangered species may find habitat on the island enhanced. Both seabeach amaranth and piping plovers, for example, need the sand flats created when storm waves wash over the island. Higher sea levels, plus an increase in the severity and number of storms caused by warming seas, means that waves will wash across the island more often. More frequent overwash means more habitat for amaranth and plovers, up to a point. Other species with different needs may not fare as well, and storms that are too frequent will wash even the sand-flat dwellers away.
Once upon a time, the loss of individual barrier islands would only have displaced natural coastal communities to other islands, or to the newly exposed mainland. Change is typical for barrier islands, and the number and location of barrier islands has varied historically. Unfortunately, the guiding rationale for the creation of parks is that by dedicating some land to wildlife and nature-based recreation, a portion of these resources will be protected in perpetuity. Meanwhile, surrounding lands are converted to farmland or beach-font resorts, because the need to preserve wild lands has supposedly been taken care of.
The very rapid change Assateague is beginning to undergo is at odds with its designation as anything in perpetuity. The island cannot serve as a refuge if it is flooded.
The Park Service as a whole is making plans based on multiple possible climate change scenarios for the next few decades. These scenarios are based on the various plausible emission rates. The research that will allow the park to develop specific scenarios for its own island has only begun. As Mr. Hulslander points out, these are planning tools, not predictions. If the island does X, the rangers are prepared to do Y. Some, or all, of the infrastructure on the island may be moved to the mainland. Some camping may also be moved to the mainland.
It is sobering to consider that nearby islands, such as Fenwick, are subject to the same pressures from sea level rise and increased storms. Ocean City, Maryland, which sits on Fenwick Island, can hardly be moved to the mainland. The city is fighting the sea by piling the beach with extra sand, for however long they can keep up that expense. The people who live on that island are vulnerable.
It is sobering, too, to consider that Assateague Island National Seashore is only about fifty years old. It is possible that, barring a miracle of public willingness to deal with global warming, some of the people who saw it win Federal protection may live to see the island break.