The Climate in Emergency

A weekly blog on science, news, and ideas related to climate change


Two Degrees of Separation

Last week, as sometimes happens, I got curious.

While writing–once again–about how the world must stay under 2° C. of warming, I suddenly realized I didn’t know where this number came from. Climate writers frequently assert that if the Earth warms more than that, we will cross a tipping point beyond which climate catastrophe will likely occur. That’s plausible, since tipping points like that do exist. But I had never encountered any explanation of why the tipping point is there or how we discovered it. So, I went hunting and found a 2010 paper cleverly titled Three Views of Two Degrees.

It turns out that 2° C isn’t a scientific limit at all, because current science gives us not just one number but rather a whole cloud of numbers. 2° C is instead, a convenient shorthand for that cloud and it is a rallying cry. And it probably isn’t enough.

Who Said Two Degrees

The 2° C limit was originally a rough estimate made by an economist in the 1970’s. W.D. Nordhous was interested in climate policy, which he approached from a perspective of cost-benefit analysis. He assumed that getting off fossil fuel would cost something and that climate change would also cost something, therefore we should craft climate policy so as to use fossil fuel right up until the point where continuing to do so costs more money than it saves. At that point, we should stop. Nordhous needed some estimate of where that that point might be, so he took a look at the fairly basic information available at the time and concluded that over the past several hundred thousand years the climate has never been more than 2° C warmer than it was at the start of the industrial revolution. He reasoned that exceeding the normal variation would be bad.

2° C itself was, of course, secondary, simply a plausible example of the kind of target Nordhaus wanted. The main point was the principle of the cost/benefit analysis. The thing is, Nordhous wasn’t the only one who needed a definite number for the sake of discussion. It’s simply easier to talk about policy, and easier to run climate models, if you have a single number to work with instead of what the research itself often presents, which is a whole group of interrelated ranges. And so, the 2° C figure has become popular far beyond Nordhous’s original discussion of costs and benefits.

That 2° C was used during a UNFCCC (United Nations Framing Convention on Climate Change) conference in Germany in 1995 probably has a lot to do with its popularity. Angela Merkel, who was Germany’s Environment Minister at the time, chaired that conference and was apparently very impressed. She was instrumental in writing the 2° C goal into the preliminary agreement signed in Copenhagen in 2010. Also, “2” is a nice, whole number, easy to remember. Note that even in America, no one refers to the limit as 3.6° F.

Is 2° C a Real Limit?

Yes and no.

More recent research has confirmed that a 2° C rise would, indeed, take us into temperature ranges the world hasn’t seen in hundreds of thousands of years. In that, Nordhaus was quite correct. However, the climate system has not one tipping point but several; some kick in above 2° C, others kick in below–and there are some, doubtless, that we don’t know about yet.

More importantly, the premise of the limit is flawed.

First, the average temperature of the planet is not the real problem–the real problem is the speed at which the climate changes. As climate deniers are fond of pointing out, Earth’s climate is always changing and has in the past been radically different than it is today. There have been forests in the Antarctic and there have been glaciers in New England; in either case, Earth had rich, vibrant ecosystems. Human society has also weathered climate changes and can obviously do so again. But adaptation, both human and otherwise, takes time. And right now, we’re not getting it.

Second, even if climate catastrophe itself begins only after 2° C of warming (which is questionable), there is a lot that can go very seriously wrong–and some of it has already happened–short of catastrophe. Sea level rise provides the most clear-cut example, since it is unambiguously caused by global warming and higher seas unambiguously cause more severe coastal flooding. Whole nations are at risk of going out of existence. We are also losing glaciers that provide drinking water to huge human populations, seeing increases in dangerously extreme weather events…arguably, global warming may already be contributing to food insecurity, and hence to social and political tension, in the Middle East. A mass extinction is underway. All this is pretty catastrophic, if you happen to be in the middle of it. Nordhous’s original proposal, that we allow the climate to warm up until the 2° C limit so as to make more money off of fossil fuels until then, is heartless in the face of people who are dying of climate change already.

Is 2° C a Useful Goal?

Of course, 2° C is no longer being considered as the amount of warming to allow before getting off fossil fuel. Instead, it represents the course of immediate, aggressive emissions reductions–the closest thing to stopping greenhouse gas emissions today that anybody considers plausible.

Some are calling even this goal unrealistic, arguing that 2° C be abandoned as pointless an unattainable.

It’s not that cutting emissions is not technically feasible. If humanity collectively turned off the machines today, the post-petroleum age would begin tomorrow (greenhouse gas emissions would not stop quite so fast–natural gas wells would still leak, for example–but these would have minimal effect). We just don’t want to do that.

There are good reasons for not simply turning the machines off–I expect that such a sudden shift would cause widespread panic and economic collapse, for one–but not all the reasons out there are good. The fact of the matter is that some people want power and money and luxury and are willing to delay climate sanity and climate justice to get it.

But the thing is, the atmosphere doesn’t care what is politically or technical feasible–if the planet warms by more than 2° C, then whatever happens will happen, be it climate catastrophe or not. We have the option to let go of a goal, but we do not have the option to decline the consequences of our actions.

The fact we are faced with is that we must, as a planet, get off fossil fuel and address other causes of anthropogenic climate change (cement production, deforestation, etc.) as soon as possible because people are dying and ecosystems are collapsing and will continue to do so as long as we keep warping the sky as we are. If 2° C  works as a rallying point towards that end, a finite shorthand to use instead of the more amorphous “immediately,” then well and good. If some other goal works better, then let’s use that instead.

Because while 2° C is not itself a scientifically based deadline, the urgency that now informs its use does have a basis in science.

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Solutions that Aren’t

Occasionally, we hear nuclear power, natural gas, or even cold fusion advanced as solutions–or at least partial solutions–to the climate crisis. It is true that each of these has the potential to give us energy with much lower greenhouse gas emissions than coal or petroleum products. It’s also true that each has obvious drawbacks–existing forms of nuclear power plant blow up occasionally, natural gas is fracking awful, and cold fusion might not even exist. But, proponents assure us, all these are surmountable problems and we shouldn’t hesitate to use all available tools when the climate is on the line.

Yes, I’m being flippant on purpose.

But as obvious as the drawbacks are, the argument for giving all available options a try does have a certain merit; the drowning should not question the life-preserver, after all. As usual, a little bit of knowledge is dangerous, because it allows two conflicting arguments to each be framed in terms that appear to make complete sense.  That’s why I want to go into detail about all the various reasons why these solutions aren’t really solutions at all–and what the real solution is.

Nuclear Power

Yes, nuclear power plants–technically, nuclear fission plants, because their energy comes from atomic nuclei breaking apart–do sometimes blow up. They don’t do so very often, so there is an argument to be made that the small risk of catastrophic failure is worth the certainty of low-carbon energy. The counter-argument is that even a small risk of catastrophe is too high. We can leave that debate to philosophers, because even a perfectly functioning nuclear power plant produces radioactive waste that nobody really knows what to do with. In other words, there’s going to be a disaster even if the plant functions perfectly–it will just be a slower and less dramatic disaster.

Perhaps more importantly for this discussion, nuclear power isn’t free of greenhouse gas emissions. While it’s true that a plant in operation produces only heat, steam, and nuclear waste (the steam spins turbines, generating electricity), virtually every other step in the process, from mining uranium to building and eventually de-commissioning the plant, releases greenhouse gasses. Estimates of how much nuclear power plants actually add to the greenhouse effect vary a lot,  though the extremes on either side suffer from clear methodological problems. 66 grams of carbon dioxide equivalent per kilowatt hour (gCO2e/kWh) is a reasonable, middle of the road figure. That’s about a tenth of fossil fuel alternatives, but it’s not nothing.

True, as long as fossil fuels power most industry and transportation no power installation of any type is greenhouse-free, but wind farms only have about 10 gCO2e/kWh. That’s one sixth of nuclear’s figure, and wind farms  never blow up.

And on top from the shortcomings nuclear has in the abstract, the practical limitations of the real world create two more serious problems. First, uranium, like fossil fuel, is not a renewable resource. Eventually, we’ll run out of it. As supplies start to run low, the nuclear industry would find itself in the same position the fossil fuel industry is now–forced to exploit ores of poorer quality or that are harder to get to.  The harder ore is to mine, and the more ore must be processed for the same amount of energy, the higher the carbon footprint of nuclear power will be.

Second, switching from fossil fuel to nuclear fission would involve building a lot more nuclear power plants., something like a new plant every week for decades on end. Since 12% of a nuclear plant’s carbon emissions come from its construction alone (not counting mining and processing its initial supply of fuel), it’s not at all clear that building all those plants that quickly would really reduce our collective carbon footprint much. More importantly, building a nuclear plant is incredibly expensive and time-consuming–a new 1,000 megawatt facility takes ten years and three billion dollars. And that’s after the plant’s owners have  found a location willing to host a political hot potato that could blow up. These things are not good investments. Nobody is going to build enough of them to replace fossil fuel any time soon.

Natural Gas

Natural gas, which is mostly methane, has been touted as a bridge fuel, a lower-carbon option that we can use until we can get off fossil fuel entirely. It is true that burning methane produces much less carbon dioxide than other fossil fuels do, but its carbon footprint is still pretty big–six times that of nuclear, for example. Methane is also itself a greenhouse gas, and as such is much more powerful than carbon dioxide. Exploiting natural gas inevitably results in some of the stuff leaking–in fact, about a tenth of the United States’ current methane emissions come from leaks at a single cluster of facilities. I don’t know whether anyone has figured the greenhouse effect of leaked methane into the carbon footprint of natural gas, but it’s a good bet this fuel is not the panacea it’s claimed to be. And then there is fracking, the dominant technique for acquiring natural gas, which carries its own high environmental cost.

To be clear, burning methane for energy is not always a bad thing. Once methane is at the surface and about to be released into the sky, burning it is the best thing to do, since that converts the methane to carbon dioxide, which is a weaker greenhouse gas. Electricity generated by burning landfill gas, which is what my husband and I buy, actually has a carbon footprint of less than zero as a result. Also, methane produced by decomposition recently–biogas or landfill gas, not natural gas–generally doesn’t change the planet’s carbon budget much because those carbon compounds were in circulation already (there are exceptions, of course). Methane has a place as a fuel in a post-petroleum world. It is only its fossil fuel form–natural gas–that doesn’t.

The big problem with natural gas is not even fracking or the details of its carbon content. The big problem is that the more natural gas we harvest, the cheaper it will get. Low costs drive more consumption. We could end up burning more fossil fuel than we otherwise would, offsetting the value of a switch from coal to natural gas. Investing in new natural gas infrastructure would also make it harder and more expensive to switch to renewable fuel later. As a bridge fuel, it’s a bridge to nowhere because using natural gas makes switching to renewables less likely.

Cold Fusion

Cold fusion is a form of nuclear power in which energy is harvested from the combination of small atomic nuclei, rather than the splitting of large ones, as in standard fission power plants. The trouble with it as a power source, is that fusion needs very high temperatures in order to get going–like the inside of a star or a hydrogen bomb. Cold fusion involves somehow persuading this reaction to occur at more reasonable temperatures (not necessarily cold by human standards) so we can put it inside a power plant. Science fiction writers have long assumed that someday this puzzle will be solved and we will then have cheap, abundant energy with no pollution or radioactive waste forever.

Whether the technology is anything more than a sci-fi trope hasn’t been clear. Every few years, a team announces it has a cold-fusion device, but none actually pan out.

All that could be changing. Cold fusion (sometimes referred to by other names) has received more attention from researchers in recent years, with some apparent success. So cheap, abundant energy with no pollution of any kind might really be a thing soon. That’s great, right?

Maybe not.

The problem is that at least part of the issue with fossil fuel is precisely that it is a cheap and abundant energy source, and altering the energy balance of a complex system (like the biosphere) always alters the way that system functions and not always in a good way. Most if not all of our current environmental problems are a direct result of our species having an energy budget out of proportion to our other resources, like arable land, potable water, and the various mineral ores. More energy means we can use resources faster, which in the short term provided the illusion of having more resources. Our population ballooned into the billions and the lucky among us became the wealthiest people the world has ever known. In the longer term, faster resource use has come with a huge cost in terms of habitat destruction, pollution, soil exhaustion, and everything else.

Here is an analogy.

Let’s say you have a large pasture with a stream running through it in which you want to keep horses. The number of horses you can keep is limited by the amount of grass your pasture can grow. Fine, but you want more horses, so you buy hay to supplement your grass. Now, your pasture can hold more horses and you like that, so you keep adding more hay. If you add an infinite amount of hay, can you have an infinite number of horses? No, because growing grass wasn’t the only thing your pasture was doing–it was also providing your animals with drinking water and room to move around, plus recycling their feces and urine into fertile soil. If you keep adding horses and more hay, at some point your pasture is going to get overwhelmed and stop providing its other services. Your animals won’t starve, but they’ll end up standing knee-deep in their own waste, with nothing but sewage to drink and hardly any room to move around.

Adding more energy to the human economy is like adding more hay to the horse pasture–by removing one limitation, we free ourselves to exceed the other limitations that are still there. Global warming is the most obvious sign that fossil fuel is destabilizing the planet, and it is possible to imagine alternate energy sources, like cold fusion, that don’t change the climate. But those alternatives will almost certainly destabilize the system in some other way, because that is what adding cheap, abundant energy does.

So, What Can We Do?

The thing is, we can imagine inventing social and economic structures that would allow us to use cold fusion safely. We can imagine nuclear fission plants designed so that they do not blow up and do not create nuclear waste. We can imagine natural gas installations that do not leak. All of the drawbacks for all of these energy sources could, in theory, have work-arounds such that they can live up to their promises, but those developments are in the future if they are anywhere at all.

There is only one solution that requires no additional technology and has been proven 100% effective already; use less energy.

Yes, we’ll need some infrastructure changes, and some new inventions would be useful for letting us keep at least some aspects of our comfortable lifestyles. But, basically, we could stop warping the sky tomorrow by just turning the machines off. Every day we put off that decision is a day we change the climate.


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Methane Surprise!

This week, the internet is full of the discovery of an unexpected methane “hotspot” in the Four Corners region of the United States. A hotspot, in this context, is an unusually high concentration of the gas in one particular area–the highest such concentration in the country, although there are several other such hotspots elsewhere on the planet.

Obviously, the big questions are where did this plume of gas come from and can we–or should we–do anything about it. After all, methane is a greenhouse gas much more powerful than carbon dioxide.

The short version of the story is that the plume was discovered when researchers from NASA  and from the University of Michigan analyzed data collected by a European satellite between 2003 and 2009. They then compared that data to other data collected from a ground-based measuring station and concluded that yes, indeed, there is a lot of methane there–almost 10% of the country’s total methane output every year comes from this spot.. The San Juan Basin has been and continues to be heavily exploited for fossil fuel of various types, including natural gas, which is mostly methane. There are, of course, other areas being exploited for natural gas, but none produce so intense a methane plume. The Four Corners area is unusual simply because its equipment (and possibly its rocks as well) are very leaky. That means that yes, we can do something about it, and should; the owners of the equipment should stop the leaks.

Unfortunately, a lot of media outlets, including the venerable Associated Press, have apparently put out stories without actually reading all of the NASA press release, because they variously blame the plume on fracking, coal, or venting of natural gas during coal mining. It’s interesting to note that even generally reliable sources can sometimes be wrong. It’s best to go back to the original source whenever possible, in this case a scientific paper published in a journal called Geophysical Research Letters.

Unfortunately, I cannot access the paper because it’s behind a pay wall that I do not have the cash to scale (I am a poor, humble science writer….).  And the sources I can access, so far, leave some of my other questions unaddressed.

But the information I can access still leaves a lot of questions unanswered. Perhaps most importantly, why was this gas plume such a surprise? Apparently, the researchers initially assumed the anomalous reading had to be an equipment malfunction, not a real gas plume.. The real headline here is not that this one spot has a lot of methane but that the previous estimates of methane emissions globally were wrong, possibly really wrong. But why and how? The obvious answer is that the satellites can sense things that ground-based instruments cannot, not that satellites are more accurate (they aren’t) but that they can see places that ground-based sensors cannot access for whatever reason. But in this case researchers used ground-based sensors to check the satellite’s results, so obviously the San Juan Basin is not one of those inaccessible areas.

If we don’t know how much methane is coming out of the ground, our predictions for climate change will be off. If we don’t know where the methane is coming from, we can’t find ways to turn off the flow. We have better answers now, thanks to this discovery, than we did before, and that’s a good thing. President Obama has included looking for methane leaks and addressing them in his plan to stop changing the climate. That’s also a good thing. But it’s odd that none of the sources I’ve read thought it important to report why we didn’t have this information before.

It’s also odd that petroleum industry leaders have downplayed the discovery, arguing (incorrectly) that the methane plume does not matter. After all, the leaks at the San Juan Basin amount to nearly one trillion cubic feet of natural gas. At current prices, and depending on whether we’re talking industrial or residential customers, that could be anywhere from five to seventeen million dollars worth of inventory that is just flying off into the sky there. You’d think somebody would care about that.

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On Natural Gas

So, this has been bothering me for a while now. One of the arguments for fracking–an environmentally destructive method of extracting natural gas–is that it is a relatively clean fuel with a lower carbon footprint than coal or petroleum products. How could any fossil fuel have a lower carbon footprint? Isn’t the chemistry of burning carbon compounds basically the same everywhere?

Well, it turns out that no, the chemistry isn’t always the same. Natural gas is relatively clean, with a lower carbon footprint. There are some complications, of course.

Some Chemistry

Natural gas is so called in contrast to manufactured gas, which was typically made from coal. Manufactured gas was very popular through the 1800’s and early 1900’s. The gas lights of gas-lit London (and elsewhere) burned manufactured gas, as did the household ovens that were so tragically easy to use in suicide–manufactured gas is very toxic. The manufacturing process for  gas was an environmental nightmare.

Natural gas, in contrast, exists in gaseous form naturally, hence the name. It burns relatively clean. A natural gas oven cannot kill a person (unless the gas explodes), so the switchover actually caused a dramatic drop in suicide rates–apparently, making self-injury just a little harder gives a lot of people enough time to change their minds..

Natural gas is mostly methane, which really does release less carbon dioxide per unite of heat released than any of the other fossil fuels.

This is because the energy released from burning any substance comes from all of the chemical reactions that occur during the fire. All fossil fuels are hydrocarbons–chemical compounds made mostly out of carbon and hydrogen. When these burn, the carbon combines with oxygen, releasing energy and creating carbon dioxide. But the hydrogen also combines with oxygen, a second chemical reaction–this one releases heat, too, but creates only water.

Because methane has the least number of carbon atoms per hydrogen atoms of any fossil fuel, burning it creates the least amount of carbon dioxide per unit of heat–but by the same principle, burning methane produces more water.

Water vapor is also a greenhouse gas.

What About Water Vapor?

Water vapor is our most important greenhouse gas. Most of it is natural; humans didn’t create the greenhouse effect, we’re just adding to it.

But human activity is adding water vapor to the sky. Besides the chemical production of water through burning fossil fuel, irrigation and other industry exposes more water to evaporation (and transpiration by plants). And, the warmer the planet gets, the more water the atmosphere can hold and so the more water is sucked up into the sky. This is part of how heat waves make droughts worse.

So, what is all this extra water vapor doing to the climate?

It’s hard to tell for sure, because there is a lot scientists still don’t know about the hydrological cycle–including how much water vapor, exactly, is in the sky. Humidity is very variable, so, depending on where and when you measure, the atmospheric concentration of water vapor could be anywhere from zero to 4%.

Climate scientists do know the feedback loop between hotter weather and increased evaporation is very serious. The more water evaporates, the hotter the planet gets, and the hotter the planet gets, the more water evaporates.  This is just one of the several feedback loops that could easily make global warming become a frighteningly self-exacerbating problem.

But the extra water vapor we add directly (through irrigation, and so forth) it more confusing. Climate scientists typically ignore this extra humidity, in part because it isn’t clear that it has a global impact. A huge amount of water goes up into the sky–the entire flow of the Colorado River and most of the Aral Sea, for example, both are sucked up by human activity and almost all of that water either evaporates or is transpired. But at least some of that water probably falls back down again pretty quickly, so the total amount of water vapor in the air might not increase all that much. Still, at least some of that water vapor probably stays up there for a while, plus both  groundwater mining (pumping well water out faster than it can recharge) and fossil fuel use add water to the cycle that wasn’t in it at all before. It seems plausible that there is at least as much extra water vapor in the sky as extra carbon dioxide. That must be having some effect.

Anthropogentic (human-caused) water vapor could be one of the things science is wrong to ignore. But on the other hand, there is a lot more water vapor than carbon dioxide up there. The concentration of CO2 has gone up by about 100 parts per million (PPM) since the Industrial Revolution, meaning that just over a third of what’s in the atmosphere is our doing. In contrast, if the concentration of water vapor has also gone up by about 100 PPM as a direct result of human activity (that is, not counting the feedback loop), then only about one ten-thousanth of the water vapor up there is our doing. The extra might well be lost in the shuffle.

The above figure assumes that the global concentration of water vapor is 1% which, as noted earlier, might well be wrong–the true figure could be anywhere from 4% to zero, but given how much of the planet is either ocean or humid landscape, 1% seems plausible. The point is that, whatever the real numbers are, we’re looking at a difference of several orders of magnitude between the concentrations of the two gases. Of course, while an extra 1oo ppm of water vapor might mean nothing over, say, a rainforest, over a desert where natural humidity approaches zero, the difference might be quite real. So, whether anthropogenic water vapor matters might therefore be a very complex question, depending on where the increase occurs and what happens to the global climate if certain areas warm disproportionately.

The reason I bring all this up is that while coal is a very dirty, destructive fuel on almost any conceivable level, burning it produces no water vapor at all. When methane (natural gas) burns, for every one molecule of carbon dioxide produced, we get two molecules of water.

Bringing It All Together

On balance, I’d say that burning methane is better for the sky than coal is, and may be better than gasoline and other petroleum products. Much of our natural gas now comes from hydraulic fracturing, or fracking, which is an environmental horror show (flammable well-water, increasing earthquakes), but so is coal mining (mountain-top removal) and petroleum (oil spills, groundwater contamination). The EPA’s new rules for CO2 emissions will probably encourage the natural gas industry at the expense of the coal industry, and that’s ok.

But the issue with water vapor is only one place where the environmental impact of natural gas might be more complex than it sounds. Clearly, the stuff is no panacea.

Ultimately, we’re going to have to get off fossil fuel entirely, and that is where our efforts need to go–towards renewable energy sources and energy conservation. Anything else is probably a distraction, although any step that lowers our carbon emissions is an improvement and needs support.