Nuclear Power: Savings lives

Nuclear power has saved over 1.8 million lives by replacing fossil fuel power sources.

A nuclear power plant!

I've mentioned that fossil fuel power plants kill people and shorten lives by emitting not only particulate matter and smog normally associated with pollution, but also NOx (natural gas power plants produce almost no particulate matter, but any time anything is combusted, the combustion process in a nitrogen rich atmosphere (78% on Earth) produces NOx, so natural gas power plants do produce NOx).

Coal fired power plants, even clean ones, belch yuckies into the air.

Shortly after harping on exactly this for several posts, a journal article came out that exonerated my aggressive stance on how nuclear power saves lives rather than ending them through nuclear disasters. Nuclear power has saved over 1.8 million lives, according to this peer-reviewed research. The authors didn't include long-term health ailments and non-death causing heart attacks related to climate change. Only death: full stop. They go on to say that replacing nuclear power with natural gas would cause 400,000 deaths by 2050. Replacing them with coal would cause 7 million. Meanwhile, the best estimates of long-term deaths caused by radiation exposure from the Chernobyl meltdown, mining uranium, and building nuclear power plants stands at about 5,000 No deaths arose from Three Mile Island or Fukushima. What about the radiation that Fukushima is spilling out into the ocean? It's less than 1/20th the radiation levels found in a banana.

I am a banana. Eating one of me makes you ingest more radiation than Fukushima ever will.

I am a banana. Eating one of me makes you ingest more radiation than Fukushima ever will.

Critics are quick to point out that renewables like wind are cheaper and more effective at reducing CO2 emissions than nuclear. Great. Let's build more wind power. Except that there are not sufficiently good places to make wind effectively and cheaply. In an exhaustive (and depressing) article on the state of nuclear energy construction, it is pointed out that Germany has an installed capacity (recall, installed capacity is simply the name-plate power generation of a plant/turbine at best-case scenario) of 76GW of renewable energy. They then compared this to all of France's installed capacity of Nuclear at 63.1 GW. But, as we have talked about, renewables don't always work. While France's nuclear generators put out 407 TWh in 2012, Germany's renewables generated 136 TWh despite their larger capacity.

"Except like Jason's former manager at JPMorgan, I only work under ideal conditions!"

"Except like Jason's former manager at JPMorgan, I only work under ideal conditions!"

Moreover, Germany pledged to phase out nuclear power after Fukushima. What did they replace it with? Not renewables. Coal fired power plants. Meanwhile, as the US expands power generation from natural gas and ceased buying coal from the US, US coal producers are finding a new market for coal in Germany.

So let's look at Fukushima a bit more. Several things are bad about fukushima. First, it melted down when a tsunami overtopped its protective walls. The US Nuclear Regulatory Commission (NRC) had told Japan 20 years ago that their Fukushima walls were too low and they could be overtopped by a very realistic earthquake scenario. And now after the disaster, groundwater contamination with (less than 1/20th of a banana's levels) radiation is all a concern. Guess what? The NRC warned Fukushima to get their groundwater issue under control three years before the Fukushima meltdown.

That's right. The US NRC predicted that Fukushima was going to happen, and told Japan to get their house in order.

NRC: Telling Japan what to do since 1980. "We don't have much of a job to do in the US anymore since we haven't built a power plant in decades"

The US has a nuclear meltdown, too. You know what the consequences were? Pretty much nothing. It cost a billion dollar to clean up. That is a huge sum. But the meltdown was well-handled. And a lot was learned from the meltdown.

My point is, the US has it's matters sorted out when it comes to nuclear safety. And we are good at identifying risks in other parts of the world.

Finally, here's the big one, new reactor designs wouldn't allow for either three mile island or Fukushima to happen. With these new reactors, in the event of mechanical failure of the passive systems, the worst case scenario of the new designs is that it would take 3 full days before even needing to worry about meltdown beginning, leaving plenty of time to deal with the situation.

So yes. There are risks with nuclear. But there are guaranteed deaths with coal and natural gas.

The best solution by far is avoiding building new power plants and to massively increase efficiency and conservation. But people are slow at changing, and we aren't gonna change our lifestyles fast enough in the western world to avoid expansion of power use, and the developing world needs to build a ton of power capacity.

So let's stop being scared of nuclear power, cause it's saving lives rather than costing them.

Thanks for reading,

- Jason Munster

Appendix

Oh, but what is this section? Just a bunch of extra information. Check out how long it takes for various countries to build nuclear reactors:

What are Pakistan and India doing that they can build nukes in 5 years?!?

Average, min, and max times of nuclear plant construction for countries that have built them. Source

Hokay, so. I need to acknowledge the bad parts of nuclear power. The real ones, not the fear-mongering that happens.

First, nuclear power is more expensive than on-shore wind (which is a limited resource, there are not infinite good places to put wind farms), coal, and natural gas. There is no doubt about that. If we switched everything to nuclear, many parts of the US that don't have high electricity prices will experience a rate shock. That is, their electricity bills will rise. But hey, remember what we said earlier about efficiency and conservation being the best way to save lives and to arrest climate change? Slightly higher electricity prices would promote this conservation. The initial rate shock would be a bit of an issue, but I am betting that nuclear power's opponents overstate it.

Second, there is an alternative to nuclear that I want to acknowledge, with a caveat. Renewables can't provide baseload power. But renewables paired with load-following natural-gas fired plants can (recall from a prior article that gas turbine based power plants can spin up very fast, and no other major power plant type can) (we don't count hydro as a major power type because we can't build more hydro in the US, we are tapped [punny]). This is by far better than coal, and better than gas alone. But it still burns gas, which produces CO2 and kills people and causes asthma.

Solving the Climate Problem

I started this site to get practice in writing science for the general populace. I've slacked off because I am a bit bored of reaching for topics. More importantly, I've been playing rugby with HBSRFC.

So here it is. A generalized and very incomplete version of my view on climate change, who it will affect most, and what we can do about it.

CO2, The Ugly One That Won't Leave You Alone

CO2 stays in the environment for more than 40,000 years. That is longer than nuclear waste lasts. Moreover, its effects are experiences by every person on the planet. What we do now has an effect on the entire planet. Luckily, technology will probably be able to fix this eventually. We can't count on this now, though.

Energy and Climate Change, How They Relate

Climate change is caused by emissions of CO2 by energy use, methane by agriculture and other things, and a host of other very powerful chemicals that are emitted from industry.

How do we solve climate change? The answer is straightforward, but far from simple: use much less energy from sources that produce CO2. Either switch to "green" tech, or conserve. Buy less things that require all the energy to produce. Travel less, or travel in ways that produce less greenhouse gases. Make fewer babies. None of these are easily accomplished, unless you are poor and can't afford any of them. Even then, everyone is striving for a wealthier, more CO2-heavy lifestyle.

So let's assume for a second that people aren't going to change their lifestyles and conserve. We need ways to get energy without belching CO2 everywhere.

Live in Smaller Houses, Buy Less Stuff

You can't convince Americans to live in houses that are the size that Europeans live in and you can't convince them to give up their cars to take public transportation and live in cities (at least in the short term). Houses require energy to heat and cool. Smaller houses mean fewer drafts, leading to less heating and cooling needs.

How about green energy? We have reviewed those technologies. There isn't enough wind to provide sufficient wind power, and the wind isn't always blowing, so sometimes we won't have power when we want it. Hydro power is pretty much fully tapped. Tidal power is a joke in the big scheme. Solar could be an option, but it is currently far too expensive. It is not "deployable" in that with solar, you only get what the sun decides, so we will always need some backup power that can be turned on when we want. Solar doesn't work well at night, for instance. Moreover, the best places for solar are far from cities, so figuring out how to get the electricity from the countryside to the cities is a monumental task, especially in the US (even with eminent domain, getting the land to be the transmission lines through several states would be nearly impossible). So here we stand with three good reasons that solar won't solve our problem in the near future, and with the other resources insufficient. Pretty much, even if we do use solar to solve a lot of our problems, we still need some other energy source to provide baseline power.

Too small! Turn back!

What about buying less stuff? The amount of CO2 that goes into making cars, laptops, etc., is pretty big. How much stuff do you buy that you never use afterwards? Or you maybe use once a year or two? All of that, you could have rented, saved money, and saved space. Even better? The things that go into making electronics like cellphones are not easy to pull out of the ground. Tantalum in your cell phone is pretty much produced by indentured servitude in Africa. The other stuff that goes into electronics, the rare earth metals, these are not so rare. It just turns out that it is difficult to produce it without destroying the environment. The US has plenty of rare earth's the reason it is done in China is that they don't mind wrecking the environment and their workers (see bottom of that post). Yeah, we need electronics to communicate and keep things moving. We don't need a new iphone every 6 months. Those things last at least 2 years.

Energy for Transportation

This is a much larger hurtle. 35% of US energy consumption is in transportation. Transportation requires that the energy source be within the vehicle (unless you are in South Korea, where the energy source is induction and is beneath the road. Pretty badass, if you ask me). Batteries currently weigh a lot, don't have nearly as much energy per pound as gasoline, and require a long time to charge. The problem is not as bleak as it seems, however. Most driving in the US could easily be done with all-electric cars.

Your bus is ugly, but it charges while driving without producing its own CO2. Well done, South Korea.

Cars

I've also written about Electric Cars.

This is an area with a lot of potential. 120 million Americans commute to work by car. The average person lives fewer than 20 miles from work. Substantially all of them commute alone. The Nissan Leaf gets 75 miles before it needs to be recharged. The Tesla model S goes about 275 miles. No matter what the source of energy for an electric car, it produces less CO2 than a normal car. Going by the numbers available on these cars, we see that with the standard US energy mix (some renewables, lots of nuclear, a whole lot of natural gas), they produce between 33% and 50% the CO2 as a combustion engine.

Bicycles

I've written about bicycling. It's good for you, and saves the environment. Unless you eat only beef. Then you have other problems.

Power Generation: What Works

Wind power makes sense everywhere that there is a lot of wind, as long as it is onshore. Wind is pretty much going up everywhere that makes sense. It costs less than a new coal power plant, and is far cleaner.

Solar power is expensive. Is there anywhere it works well? Sure, just take a look at the electricity rates paid by different types of consumers. Commercial real-estate (stores, offices) and residential places (our homes) pay a huge premium on electricity. In most states, residents and commercial consumers pay nearly 15 cents per kwh, while industrial consumers pay closer to 7 center for a kwh. How does this stack up to costs to produce? Let's return to my favorite chart:

Table 1. Estimated levelized cost of new generation resources, 2018 
U.S. average levelized costs (2011 $/megawatthour) for plants entering service in 2018
Plant type Capacity factor (%) Levelized capital cost Fixed O&M Variable O&M (including fuel) Transmission investment Total system levelized cost
Dispatchable Technologies
Conventional Coal 85 65.7 4.1 29.2 1.2 100.1
Advanced Coal 85 84.4 6.8 30.7 1.2 123.0
Advanced Coal with CCS 85 88.4 8.8 37.2 1.2 135.5
Natural Gas-fired
Conventional Combined Cycle 87 15.8 1.7 48.4 1.2 67.1
Advanced Combined Cycle 87 17.4 2.0 45.0 1.2 65.6
Advanced CC with CCS 87 34.0 4.1 54.1 1.2 93.4
Conventional Combustion Turbine 30 44.2 2.7 80.0 3.4 130.3
Advanced Combustion Turbine 30 30.4 2.6 68.2 3.4 104.6
Advanced Nuclear 90 83.4 11.6 12.3 1.1 108.4
Geothermal 92 76.2 12.0 0.0 1.4 89.6
Biomass 83 53.2 14.3 42.3 1.2 111.0
Non-Dispatchable Technologies
Wind 34 70.3 13.1 0.0 3.2 86.6
Wind-Offshore 37 193.4 22.4 0.0 5.7 221.5
Solar PV1 25 130.4 9.9 0.0 4.0 144.3
Solar Thermal 20 214.2 41.4 0.0 5.9 261.5
Hydro2 52 78.1 4.1 6.1 2.0 90.3
 

Solar PV costs less in sunny areas than buying from the grid, as long as you are residential or commercial. A big industrial complex gets really cheap power, so they will never use something as expensive as PV.

The Future of Solar

Even if solar power is widely deployed in the future, it doesn't work at night. A lot of people in Houston, and other places that are unlivable without modern tech, would be unhappy if they couldn't sleep in AC. We don't have massive-scale battery tech  to compensate, so we will still need baseload.

Baseload Power

There are two viable places to get baseload power. The first is nuclear power. The second is burning fossil fuels and then catching their CO2 and putting it underground.

Carbon Capture and Storage

This is a very unproven technology. We don't know if we can hold the CO2 underground forever (which is what would be necessary) or whether we can find a place for it. And there are only a few test cases for it. The numbers above are completely unreliable in terms of cost. This might be better in the future, but I would guess that it isn't viable for at least 15 years.

Another issue? You can't just start capturing CO2 emissions from any old power plant. Retrofitting the plant is expensive or impossible. Power plants are built to last 50 years. Even when we figure out carbon capture and storage, we can't easily retrofit old plants to make them work well.

Baseload?

So we need baseload. There are no green baseload sources. Making coal based powerplants green is not currently viable. Nuclear power doesn't produce much CO2, but it has nuclear waste. Nuclear waste lasts a long time. But it is the only power source that contains all its waste. It's manageable. And it decays faster than the Earth will take down CO2.

nuclear power plants are my favorite

What's the biggest problem with nuclear? I'll describe this in more detail later. The long version: it can't get financed. Short version: people are afraid of Nuclear. Cause three powerplants have blown up. Fukushima was completely preventable. The US literally told Japan twice to get their house in order, cause there was trouble.The USGS warned that the walls of Fukushima were not high enough to prevent tsunami flooding years ago. Had they followed through with the USGS recommendations, Japan would not be spewing radioactive waste into their groundwater. Moreover, the US Nuclear Regulatory Commission told Fukushima and Japan that they had a groundwater problem, and that a breach would cause widespread contamination; that if it ever melted down, it would dump nuclear waste into the ground through the water. They indicated Japan should divert the flow of the groundwater to prevent this. Still, no one died in this meltdown.

When Russia melted down a nuclear plant, it was a big mess.

When the US melted down a nuclear plant, no one was harmed and not much was released. It was just expensive to clean it.

Short version? The US is good at nuclear. Korea seems to be good at it. People shouldn't be afraid of it.

But they are. So the plants don't get financed, they don't get built, they aren't allowed to go forward.

As a result, if someone did want to finance them in the US, they would have to pay such massive interest rates that it would never pull a profit.

You know who is building them? Korea. China. Korea is also building power plants in the middle east. Other countries will follow suit. We need to get our house sorted out so our country can build power plants here and elsewhere, too.

Summing it Up

Live in smaller houses, it won't make you less happy. Buy less stuff, it also won't make you less happy. You also don't need to drive an SUV. Or drive as much as you do. Commuting sucks anyways.

Until all that happens, we still need a ton of electricity. Nuclear is probably the best way to do it for now.

That's my rant

Seriously. I'm pretty much done.

Thanks for reading all along. There might be a few more posts on this stuff.

- Jason Munster

Geoengineering

So. Science can fix anything, right? Only if we have lots of time and money. And grad students that function as indentured servants in a pyramid scheme to get tenure.

Back to the point. The truth is that science can't fix everything on short time scales. Climate is one of them. Geoengineering can help to a degree, but it will only get us part of the way there to avoid the worst consequences of climate change. Let's discuss some.

White roofs, white roads, white buildings.

Two articles back, we discussed albedo, or reflecting sunlight. Ice reflects 90%, water reflects 90%. Whatever is reflected tends to go to space and not stay in the Earth system and warm it up. In fact, whatever is absorbed then gets in the greenhouse trapping loop, warming up the Earth a good bit. Dark surfaces (our roofs, our roads, most of our buildings) reflect little and absorb a lot. So, paint them all white, and more light is reflected. Excellent!

"But Jason," you say, "Cities are only a small percentage of land area. How could this possibly help? I mean, the rest of the Earth will still absorb just as much heat. Right?"

And to you I say, "Excellent, sir! That is true. Making all our stuff white won't do much for the overall heat budget of the Earth. I am so proud of you for reading most of my website so you quickly figure stuff like that out."

So what does it do?

 

The heat island effect is based on the fact that cities are covered in dark buildings and pavement, and have a very low albedo, so they absorb heat

Cities are fucking warm. They suffer from this thing called the "heat island effect." That is a fancy way of saying that they are so dark, they absorb the sunlight and are easily 10 degrees F (around 5 degrees C) warmer than they should be. Turn everything white, and you can cool the city. This will actually have a very large effect on how hard our AC units have to work in the summer. Imagine if your city was suddenly 10 degrees F cooler. How sweet would that be? I posit that it would be pretty rad.

This one seems to help a bit, but we will still be using tons of energy and producing CO2 in all other ways. Moreover, it won't solve the problem of the agriculture, ice caps, and acidifying ocean.

Putting CO2 in the ground

There are two ideas of sequestering CO2 in the ground. The first is capturing it at the source. Like power plants. This sounds like an easy idea, but the first problem is the energy it takes to capture it. Thermal power plants take in atmospheric air. Which is 78% nitrogen, and 21% O2. Even if all the O2 were converted to CO2, what comes out of the power plant stack is still 78% nitrogen. Separating the two to store the CO2 takes more energy. In fact, the power plant is roughly 30% less efficient. So it needs to burn a lot more coal or natural gas to produce the same amount of power, and will cost a lot more to build. And any fancy idea you have to get around this 30% efficiency hit won't work. No matter what, you either have to pre-concentrate O2 to get a pure stream of CO2 on the other side, or separate the CO2 on the emission side.

The next problem is where to store it once you get it. Gases like to leak out of things. Some companies are trying to store the CO2 underground, much like petroleum is stored underground in a lot of places. This is why you need to separate it from the nitrogen in the air. There just isn't enough space to store both the CO2 and the nitrogen, and also it is expensive to pump stuff underground. Another issue is that it is unclear how long storing CO2 will last in the ground, since it more or less needs to be done indefininately.

Finally, since 35% of our energy use is from cars driving down the road, and it is impossible to capture that CO2. So Carbon Capture and Storage (CCS) from the source still won't do everything we need.

Direct Capture
The next idea is to capture CO2 directly from the air. We have increased CO2 in the atmosphere from 280 parts per million (.028%) 400ppm. The idea of direct capture is to do the opposite. Draw down the CO2 and then store it somewhere. Some might suggest we store it in trees, but that is an awful lot of trees, and unless we bury them trees somewhere underground, they are just gonna get consumed by bacteria and become CO2 again. Other options are to mechanically and chemically separate CO2 from the air, and them store it underground as above. This is very expensive. It might work in the future, but for now it won't.

The bonus of this, if it ever works, is that it is the best way to reverse our issues from an engineering standpoint. We can turn back the clock.

Stratospheric Injection

Injecting small sulfur or other particles into the atmosphere cools the entire globe by reflecting some small portion of sunlight before it hits the rest of the Earth. We know this cause when mountains like Pinatubo and St. Helens explode, they launch particles into the stratosphere and we get a cold year.

SO2 increase in the stratosphere by exploding volcano

Some people have suggested that we could do this. Just inject stuff into the stratosphere to reflect sunlight. The problem? It turns out that everything small enough to cause the proper scattering just happens to be the right size to promote adsorption of water particles. Which then allows for rapid recycling of CFCs in the stratosphere.

"But Jason," you say, "I thought recycling was good!"

Recycling plastics is good. Stratospheric recycling of CFCs is bad. Cause what happens is a CFC reacts with ozone, breaking it apart, wrecking the ozone layer, and then usually is all like, "Man, I am exhausted from catalyzing that reaction, I am gonna take a break." But that water that adsorbed onto our reflective particle provides an excellent place for it to re-radicalize. Which means it is ready to take out another Ozone particle. That's right, our CFC goes to chill out on some water droplets, effectively taking a restful timeout at a pool, and gets ready for work again destroying the ozone layer.

Let's pull this all back together. We try to put stuff in the upper stratosphere, if could make CFCs more effective at destroying the ozone layer, and then we are all screwed in a much much larger way than climate change. Cause the ozone layer is what protects us from getting fried by a lot of UV rays.

Here's where things get fun. Imagine you are a small country of 1 million people living on an island. And that island is going to get inundated with water in 20 years unless climate change is reversed. You don't give a damn about a chance of destroying the ozone layer. You only care about saving your people and your country. Stratospheric injection isn't exactly nuclear science. We aren't going to have rogue nations stumbling through how to do this, and failing all the time.

I'll leave you to ponder what all that means, cause it is more fun that way, and we are already at 1200 words.

The upshot of this is that it also fails to solve the acidifying of the ocean, we don't know how well it will work, and we don't know what will go wrong.

Solar Reflector

Another idea is to put huge mirrors in space and reflect a chunk of the sunlight coming in. This could work. Wasn't this a plot in some Bond movie, though? Also, it would be mad expensive. Probably much more expensive than some other options. And much like the option directly above, we still acidify the ocean.

Review

Hokay, so. Most of the technologies for fixing our problem don't exist, don't work, are too expensive, or could kill us all. And if they do work in the future, they won't solve all the problems we are creating. Even the one that does solve all the problems, direct capture from the atmosphere, won't do crap for our plight if we rely on that alone. As a species, we can easily outstrip any CO2 removal measures just by burning more things. Even if after rigorous testing proved all these work, we would need to some combination together to get anywhere. And even with that, we need to reduce the continued growth of emissions worldwide, otherwise no science or engineering solution will stop climate change.

Depressing, eh?

Thanks for reading,

- Jason Munster

Climate Change 2

I am not expert on different effects of climate change. But I do know a good smattering of random things. More importantly, several of my coworkers in grad school are at the forefront of the research of a lot of things here.

Here are some events relating to climate change, with indications of how much I think I know about it. So, for these things, I will have a title, than a 5 star rating for my level of confidence in the material I am presenting. 5/5 means I think I know a whole lot, 4/5 means I know what a grad student in a related field should know, and I probably am friends with one of the experts in the field, 3/5 means I am conversant in it, 2/5 means I understand it a little and have seen the math, 1/5 means I have heard of it and think it is worth mentioning.  It is important to note that anything rated 1 or 2 should be taken with a grain of salt, and should absolutely not be cited. I don't really know much about these things, other than they are possible.

Melting Ice Sheets -  3/5

A snapshot of the Arctic sea ice extent from June 2013. Area of sea ice has decreased over time

A snapshot of the Arctic sea ice extent from June 2013. Area of sea ice has decreased over time

It seems like every summer, the news programs get all abuzz over the Arctic ice extent. No matter which way it goes, they get excited. The extent is literally the surface area that this ice covers. But as we discussed on an early post about thermodynamics, the amount of heat energy you have to pump into a system does not relate to its surface area, but instead to its volume, since volume is directly related to mass. And the story of ice volume yearly minimum is more telling: the minimum ice volume in the summer has decreased by a factor of nearly 50% over the past 5 years. In other words, half of the summer ice is gone.

The areal extent of ice seems somewhat erratic. The volume measurement of arctic ice over the last 5 years is a much more important measurement

What happens when the ice goes away?

Albedo changes - everyone knows about this, so I won't rate my knowledge here. In the last post, I mentioned that ice reflects 90% of light energy, and water absorbs 90%. If the sea ice disappears, more heat can be absorbed and trapped by the Earth, causing warming to happen more quickly.

Shortwave radiation is high-energy radiation from the sun. Longwave is infrared that comes off from Earth. Ice reflects shortwave (sun) radiation.

Stronger temperature changes in high latitudes

As the planet warms, the warming will be more felt in the high latitudes (ie the Arctic and Antarctic). As you can guess, this will have feedbacks with the ice melting and albedo changes.

Projected temperature increases show that the high latitudes will have far more profound temperature increases under climate change.

The habitats of the Arctic will present another positive feedback - 5/5

This is what I study directly. I don't model this, I measure it. Well, my team does. I am a small part of that. In normal biomes, plants pull CO2 from the atmosphere and turn it into plant matter. A lot of this is leaves or grass and such. They then die, fall to the ground, and get consumed by bacteria or oxidized to become CO2 again. So most of the CO2 consumed by plants and such is recycled back into the atmosphere.

In cold places, it is different. Moss and grass grow in the summer (no trees, permafrost prevents them from ever taking root). Much of this after it dies does not get recycled to CO2 again,cause the freeze already happened and it is too cold for the stuff to become CO2. This has happened in the Arctic for 300,000 years or more. In the first 3 meters of Arctic soil, there is enough undigested carbon to double the amount of CO2 in the atmosphere. Obviously it won't all release at once, and most of it may not release. But even if a part of a percent started being released per year, it would match mankind's CO2 emissions. This hasn't started happening yet, but if it did, we'd want to work fast to reverse it if we hope to prevent climate change from jumping into a strong positive feedback loop that we cannot control.

More on this later, when I describe my actual research and what I do day to day.

Weather patterns change - 1/5

I can barely even hand-wave at this one. The ocean strongly influences atmospheric circulation patterns. Hurricanes, for instance, always form over the ocean. This is because the ocean has a ton of thermal momentum (it doesn't change temperature at the same rate as the atmosphere) and the top layer of it is well-mixed, so even if the top few inches warm up, it will rapidly be cooled off by the water beneath. The atmosphere has much less thermal momentum, mostly because it is far less dense than water. So what happens when you have an ice cap? The water-atmosphere interaction is cut off. The water is sealed away from the atmosphere, and suddenly the ocean stops controlling wind patterns and such. And then very large-scale atmosphere-driven wind patterns can develop without ocean waters impeding it. This leads to wacky weather. Like increased snow in winter at mid-latitudes, and much more variable weather. This is why we now call it climate change instead of global warming. Some places will get cooler, but the variability of weather patterns will increase because of this sort of event. Like in Boston on May 2th where we broke the record low, and then on may 29th we broke the record high. Yay more climate variability.

Drought in the US. Much of the west coast is short of water.

Drought in the US. Much of the west coast is short of water.

In addition to weather variability, some trends will be more pronounced. Dry seasons will be more dry and last longer. Rainy seasons will have more intense storms. This can be a problem, cause droughts prevent agriculture from working.

Which leads to:

Increases in Floods and Droughts - 2/5

There are floods called 100-year floods, cause they should only happen once every 100 years. Areas of Australia had two 100-year floods in a decade. This is because climate change will make large weather events, like floods and droughts, a lot more frequent.

Torrential rains flood Australia pretty frequently these days. Expect more of this in many parts of the world as climate change takes hold.

Melting Glaciers 4/5 (I hang out with the world experts on this all the time, cause they are cool)

Did you know that everything with mass exerts a gravitational force. Yes, hard to believe, but it is true! And it turns out that mountains and glaciers exert a sideways gravitational force. One that is strong enough to pull water from the oceans towards them. In other words, if the Greenland ice sheet melts, the sea level Greenland would actually drop. And the sea level around India, Africa, and South America would rise a more than you would expect. So instead of seeing 7m of sea level rise from all of Greenland melting, they might see 8m. In other words, all the poor countries that didn't put the GHGs in the atmosphere, and also cannot afford to prepare for the rise, will take the brunt of this one.

Disease - 1/5

Many people predict that certain diseases will become more rampant. Like how trees are getting destroyed all over California, because certain tree-eating bacterias and insects can survive in the slightly warmer weather. More trees and plants will die, yes. The disease part is a bit questionable how it will work. Diseases of many times will shift where they work, but it won't necessarily expand it. But just think about how much fun most of my readers (predominantly American) will have if Malaria creeps north into a bunch of our states. Overall, though, the jury is still out on this one.

Food Production difficulties - 2/5

Many staple grains, like corn and wheat, won't grow as easily if the temperature rises even 2 or 3 C. The world food supply could easily run short, especially with the combination of increasing population from 7 to 9 billion over the next 40 years or so, and the fact that as much of the world gets wealthier, they want more meat. Why is the meat thing an issue? It takes about 40 lbs. of grains and such to make 1 lbs. of cow meat. For pigs, it is much better, with a ratio of about 8. Cause pigs are excellent at turning calories into food for us. Yet another reason to like bacon, eh?

Anyways, food supplies will become more strained. It could be a very serious issue. People might fight over it. By people, I mean countries.

Also interesting, I sometimes brew beer with a guy who is one of the experts on this.

Wrapping up

I have only touched on a few things here. As more come up, I will update this post and tell people to check it out. Before leaving, let's review some of this stuff.

Wealthy countries by and large have pushed a ton of greenhouse gases into the atmosphere. It is causing climate change. Because of how gravity and glaciers work, climate change is going to effect predominantly Southern hemisphere countries. In other words, South America, Africa, areas around India, etc. Pretty much, it is going to have a more profound effect on the countries that can't afford to build walls around their cities to hold back water, and can't throw money and science at the problems as easily. Climate change already punishes poor countries cause they cannot afford to deal with the changes, but the melting glaciers problem exacerbates their situation.

One great example: If emissions of greenhouse gases are not somewhat arrested and sea level rises 1m, at least 17 million people in Bangladesh will find themselves inundated. Where are they going to go? They are surrounded by an ocean, India, Burma, and a whole slew of mountains called the Tibetan Plateau (think Himalayan mountains). India doesn't want them, they are already crowded. Burma is rather hostile. Sending 17 million climate refugees anywhere is likely to cause a problem. And that is just one country.

Hokay, that was depressing to write. To end on a cheery note, climate change will make the weather in both Canada and Siberia much nicer. Also, when the ice caps melt in the Arctic, international trade will have all new sorts of inexpensive ways to move around! This will prove useful.

Oh, one the thing.

The Arctic has a ton of resources that can be mined / produced. So when that ice melts, there will be a wealth a resources. And probably a lot of fighting over said resources.

Thanks for reading!

- Jason Munster

Climate Change

So here it is. The post on how climate change works. Today, we return to Math!

*added later: thanks to the friends who noticed typos and order of magnitude errors, and prompted me to correct them

** Comments section has been opened up.

Climate Change

Some people say that the amount of CO2 in the atmosphere is so small that it couldn't possibly do anything. They say this because if you take one million random molecules in the atmosphere, only 400 of them are CO2. Seen another way, oxygen is 21% of the atmosphere, and CO2 is .04% (It was .028% before we got started playing with things. So we raised the % of CO2 by .01)

People who believe a small perturbation cannot change a complex system are in denial. Complex systems, like the climate or our bodies, respond to some inputs very strongly. As dumb as this comparison is, lets consider a poison introduced to your body. Let's say you weigh 50kg (a little more than 100 lbs). 0.01% (this is how much we changed CO2 by) of your body weight is .005kg, or 5000mg. A lethal dose of cyanide in a human is about 1.5mg per kg of weight. For a 50kg person, this is of 75mg. 5000mg of cyanide would be overkill.

It may seem drastic to compare CO2 in the atmosphere to cyanide in the body. One causes warming in the atmosphere (at least scientists argue that), the other causes death of a single person. It may actually be somewhat an apt comparison. Without warming caused by greenhouse gases, life as we know it would not exist on Earth.

Maths!

Here I will show that without greenhouse gases, the Earth would be a frozen wasteland. CO2 and other gases trap heat, more or less preventing heat given off from the Earth from escaping by reflecting back on itself.

The heat on the Earth's surface and in its atmosphere has one major input, and one major output. The input is solar energy (we call it solar radiation. Not the same type of radiation that uranium has when it goes through a radioactive decay.). The output is radiation that the Earth gives off. As the Earth heats up, it gives off more radiation. The output of heat from the Earth needs to match the input of heat from the sun, otherwise it heats up or cools off. If the output of heat drops and the input of heat remains the same (say, for instance, that greenhouse gases prevent output of heat by trapping some of it), then the planet will retain heat until it is so warm that it gives off enough energy to again have an output that is equal to the input.

Schematic of how greenhouse gases trap and reflect heat from the Earth, preventing it from being released once it is absorbed.

Let's start from the basics, the energy emitted from the sun. If you want to take my word for this, you can skip to earth temperature calculation part

The energy emitted by the sun is based on its surface temperature. In fact, it is the surface temperature related to the 4th power (the reasons for this lie in quantum mechanics. If you are feeling smart, brave, or arrogant about your smarts, follow that link to find out why it is T^4).

Our sun puts out energy in many different wavelengths

 E_s = 4 \pi R^2_s \sigma T^4_s

Here, R is the radius of the sun,  7 \cdot 10^8 m and  \sigma is the stefan-boltzmann constant used specifically for blackbody radiation:  5.67 \cdot 10^{-8} W m^{-1} K^{-4} . The surface temperature of the sun is 5800K.

So this is how much energy is emitted in total by the sun:

 4 \cdot \pi (7 \cdot 10^8 m)^2 \cdot (5800K)^4 \cdot 5.67 \cdot 10^{-8} W m^{-1} K^{-4} = 3.95 \cdot 10^{26} W emitted by the sun.

What fraction of this hits Earth? Let's call is F_s for flux of energy to the surface of the Earth.

F_s = \frac{E_s}{4 \pi d^2} where d is the distance between the sun and Earth( 1.5 \cdot 10^{11}m )

 F_s = \frac{3.95 \cdot 10^{26} W}{4 \pi (1.5 \cdot 10^11 m)^2} = 1397 \frac{W}{m^2}

Satellite observations show the actual value is closer to 1370. So our very basic theory shows us correct within 1.5%. So far so good, as far as this basic math model goes.

So, at the equator, we get 1370 watts for every square meter of land. As you move poleward, this amount decreases by roughly a factor of cosine.

Earth's Temperature

Hokay, so before we had an equation with \sigma T^4 in it. We can get Earth's equilibrium temperature by doing all this process in reverse. One important thing to consider: not all of this light reaches the ground. A lot is reflected. White snow, for instance, reflects about 90% of light. Water absorbs about 90% of light. The factor of reflection is called albedo (we will call this A in our equations). Overall, the current albedo for Earth is about .28. In other words, 28% of light is reflected back to space.

This is kinda how albedo works

Hokay, so light hits the Earth. It hits 1/2 of the Earth, which is a globe. So the light lands on the surface, which for a globe is roughly a circle. A circle with the radius of the Earth, R_e

So the mean solar radiation absorbed by the Earth is:

F_s \pi R^2_e (1-A) / 4 pi R^2_e = F_s (1-A)/4

We can approximate the black-body temperature of the Earth to be equal to this. So

F_s (1-A)/4 = \sigma T^4_e where T_e is the temperature of the Earth

T_e = (\frac{F_s (1-A)}{4 \sigma}) ^{\frac{1}{4}}

substitute numbers in:

 (1370 Wm^{-2} \cdot .72 / (4 \cdot 5.67 \cdot 10^{-8} Wm^{-2}K^{-4})^{\frac{1}{4}} = 256 K

Note, Kelvin is just celsius temperature, except 0 kelvin is absolute zero, the coldest possible temperature in our universe. 0 kelvin is roughly -273 C. So 256 K is 17 degrees below 0C. Let me emphasize that.

From a strict radiative standpoint, the surface temperature of the Earth should be at the very warmest 17 degrees celsius below freezing.

Did we do something wrong? Nope. We forgot one very important factor. Greenhouse gases trap heat. Without CO2 and methane and water (yes, water traps heat) in our atmosphere, the Earth would be frozen solid, and there would be no life, at least not on the surface. Even the oceans would be frozen over.

How greenhouse gases absorb and trap heat

A CO2 molecule has a C in the center and two oxygens hanging off it. When light of a certain wavelength hits it, those two oxygens start vibrating faster and get excited. Which means the light was absorbed and converted to heat. It turns out that the temperature of the Earth is such that the bulk of light it emits is a wavelength that things like CO2 and H2O and CH4 can absorb. They are heated up. If this happens all over the place, the entire atmosphere heats up. And then, since everything emits light based on its heat, the CO2 molecules release some of this energy as light, again in infrared, and it has a chance of being re-absorbed by another molecule. Eventually some of these photons (the light energy) escape the Earth.

So, now we have to change our equilibrium temperature equation to have a greenhouse forcing:

T_e = (\frac{F_s (1-A)}{4 \sigma} (1-f)) ^{\frac{1}{4}} where f is the greenhouse forcing factor.

I am not going to run through this, cause everyone gets my point. Going back to our analogy, these tiny amounts of CO2 and other gases in the atmosphere make our planet livable by increasing the temperature. And the more we pump into the atmosphere, the more the atmosphere and surface of the Earth will heat up. In short, climate change is real, and it is caused by people.

Here we have CO2 concentrations over the past 400,000 years plotted against temperature. These can be derived with reasonably accuracy directly from air bubbles in ice cores that are up to 700,000 years old, or inferred from isotope ratios of oxygen (another story, another time)

Here is more recent data, with direct measurements. Yes, the axes are scaled to make the correlation stand out. The point is that the correlation between rising CO2 and temperature exists. CO2 goes up, then temperature goes up.

Here is more recent data, with direct measurements. Yes, the axes are scaled to make the correlation stand out. The point is that the correlation between rising CO2 and temperature exists. CO2 goes up, then temperature goes up.

At this point, it should be clear how important CO2 and other greenhouse gases are, and how changing GHGs by a small amount can make some pretty big changes in the complex Earth system. These conclusions are rooted in science. It's the same science that makes cars work. Anyone who believe in cars should also believe in GHGs causing climate change.

Some effects of climate change

We all have heard of sea level rise. Most people think the primary cause of all the sea level rise we have seen over the last century (about an inch every 15 years) is melting glaciers. This is untrue for most of the sea level rise of the last century. What causes it, then? Water is most dense at 4 degrees celsius. If it moves in either direction away from this, it begins to expand (as ice in one direction, as water in the other). Thermal expansion of water has caused much of the sea level rise we have seen.

Sea ice melting doesn't raise sea level at all. Because the ice contracts when it becomes water. In short, sea ice doesn't displace water. Those melting arctic ice caps aren't going to change the sea level much from melting alone* (we will get back to this later).

Melting glaciers, on the other hand, will make a difference in the future. That is water that has been removed from the ocean and placed on mountains. When it comes off those mountains, it flows to the ocean. It is estimated that the Greenland ice sheet has about 7m of sea level rise worth of water, or about 20 feet. Most of Florida would be gone in this case. NYC, Shanghai, many European cities, Vancouver, DC, Boston, etc., will be underwater. No one really knows what timescale this melting will occur at. We will cover this more in depth in another article. These may have already started to go. The average annual sea level rise for most of last century was about 1.7mm/year. In the past decade, it has doubled to about 3.4mm a year. The Greenland ice sheet has definitely been melting in recent years. It is unclear how fast this will unfold. More on that later.

*Melting Arctic ice: remember when I said that snow reflects 90% of light energy, and water absorbs 90%? What happens when we melt ice caps, then? More of the light that hits that area will be absorbed. So let's recap here. The Earth heats up. The ice caps melt, exposing water, which absorbs more light, making the Earth heat up more. This is what you call a positive feedback mechanism. It is not "positive" in that it good. Positive means that it has an accelerating effect. Normal people call this a self-perpetuating cycle. Some people call it a "vicious cycle." But we are going to call it a positive feedback mechanism, and know that in this case, it is a bad thing.

** A colleague mentioned that I should also talk about the water vapor feedback, since it is often a tool used by climate skeptics. Water vapor is a very strong greenhouse gas. When the temperature rises, more water vapor goes into the atmosphere, which can in turn raise temperature more. It sounds like a permanent positive feedback mechanism, but it has stark limits if it acts alone. But when you put CO2 into the atmosphere, it causes warming, and then causes more water vapor. In this case, we can say that water vapor amplifies CO2 greenhouse forcing. Again, the additional water vapor warming from CO2 atmospheric load increase is limited, but NASA and later studies show that in some places, the effect of water vapor can amplify the greenhouse forcing of CO2 by a factor of 2. While the theory is not perfectly understood, the observations (areas with high water vs. low water, accounting for all other types of forcing) are very good.

And now we have exceeded 2000 words.

-Jason Munster