Science Friday: Climate Change, Part 1




Currently, when sunlight falls on the Earth, about 30% is reflected—most prominently by ice, though deserts also reflect sunlight well. (The percent of incoming light a surface reflects is called its albedo. So, the Earth's average albedo is 30%, though different parts reflect varying amounts of light.) The light that isn't reflected is absorbed and converted into heat.

All objects get rid of some of their heat energy by radiation—“glowing” to convert the heat into light. Most things we encounter “glow” in the infrared, so we can't see it. Only very hot objects, like lightbulbs and the sun, glow in the visible spectrum. So, the Earth loses heat by radiating infrared light away. The amount of energy it radiates is roughly equal to the amount of radiation it absorbs—if it weren't, the system would not be in equilibrium and the temperature of the Earth would be changing rapidly.

Of course, that isn't the whole story, because we haven't accounted for the greenhouse effect. The greenhouse effect is a natural process by which certain gases, most importantly carbon dioxide (CO2) and methane, trap some of the infrared light the Earth radiates in the atmosphere. This makes the Earth warmer than it otherwise would be. It's very fortunate for us that it exists—without it, it would be too cold to support civilization as we know it.

Just because it's natural and makes our existence possible does not mean we can't hurt ourselves with it. The Mississippi River is natural, and New Orleans wouldn't exist without it, but human stupidity with a little help from nature caused it to flood the city. The dumbest of the global warming deniers claim that CO2 is fine because it's natural, but “natural” does not always mean “beneficial” or “immune to reacting violently to human stupidity.”

So, humans did a whole lot of things to put tons of CO2 and methane in the atmosphere. Since the beginning of the industrial age, atmospheric levels of CO2 have increased by more than 30%, mainly due to deforestation and the burning of fossil fuels. Methane levels have increased by more than 150% over the same time, mainly as a result of agriculture, particularly beef cows. This has strengthened the greenhouse effect, causing global temperatures to rise.

A few side effects of this warming have helped increase it. The biggest is called the ice-albedo feedback. As the Earth warms, sea ice in the Arctic melts. As the ice melts, less-reflective water is exposed to the surface. Water has a much lower albedo than ice, so it absorbs more light, and gets hotter. So, the Earth warms, causing ice to melt, causing more light to be absorbed, causing the Earth to warm, and so on.

This feedback loop is very bad for us. Unfortunately, it's not unique. As the Earth warms, permafrost melts. Permafrost has a very high CO2 and methane content that is released as it melts. So, Earth warms, melting permafrost, releasing greenhouse gases, causing the Earth to warm. Another example is how much CO2 the ocean absorbs. The ocean naturally absorbs a chunk of CO2, helping mitigate the effects of our carbon emissions. However, it absorbs less and less as it warms. This is another way global warming feeds on itself.

So, emitting as much CO2 and methane as we have opened up a really complicated can of worms. Basically, because of these feedbacks, there is a point we hopefully won't reach where even if we drop emissions to zero, we won't be able to stop runaway warming. We have to make sure we curb our emissions before we reach that point.

What happens if we don't? A lot of really bad things. And not just that it'll be uncomfortably hotter.

If temperatures rise enough to melt the Greenland and Antarctica ice sheets, global sea levels will rise a lot. More than half the world's population lives close to the sea. If sea level rises, tons of people get displaced. The map below shows what parts of the east coast would vanish into the sea in a 10 meter sea level rise (which is not the worst case scenario here.) Imagine the impact of losing Boston, New York, Virginia Beach, Wilmington, Charleston, Miami, Mobile, New Orleans, and Galveston. Then add the west coast.

It isn't just the ice at the poles that could melt, either. The Himalayas are sometimes called the “third pole” because of all the ice there. The Himalayan glaciers grow high in the mountains and flow downhill. The Ganges, Indus, Brahmaputra, Mekong, Thanlwin, Yangtze, and Yellow rivers are fed primarily by their meltwater. Most of the Chinese, Indian, Pakistani, and Southeast Asian populations depend on those rivers. If the Himalayan glaciers vanished, the economies of those countries would be devastated, and, given our close ties to them, so would ours. Compounding the problem, three of those countries are nuclear powers, so instability in the region could have dire global consequences.

The two effects I mentioned above would cause a greater displacement of people than has ever occurred. You can be sure that a global wave of refugees would have dire political and economic implications for everyone, not just those directly displaced.

Global warming would affect us many other ways, mostly bad. Most agricultural centers would become more arid and less suitable for growing crops. Diseases would grow in range and epidemics would become more common. The frequency and severity of storms would increase (imagine a few more Hurricane Katrinas.) Deserts would expand. Ultimately, North Carolinians might have to go to New Hampshire to find a climate similar to what we have now.

This is what will happen if we fail to prevent it. It is not inevitable. Over the next three weeks, I'll discuss the ways it can be stopped, and how the politics for stopping it look.

This week's science news is a little terse because I'm in a rush.

Storm Video Hatteras:

Oil Prices:

Lightning and Space Weather:

NASA & ESA team up for Mars:

Shuttle Launch:



and Greenland just might live up to its name someday ...

From Science Daily

Thank you for the great post. Humans are starting the 21st century worried about oil; we will likely end the 21st century worried about water. The graphic showing the rivers originating in the Himalyas was very cool.

I actively oppose gerrymandering. Do you?

Thanks for helping educate everyone

As Copenhagen approaches and the Kerry-Boxer bill moves through the Senate, we have to keep the pressure on Congress. It's so important to remember how urgent this is.

Different theories

I agree that there are different theories and think that there is far too much dogma and posturing by both sides. However, for me, it comes down to this: we know that C02 levels have increased dramatically. Since we only have one atmosphere, can we please err on the side of caution for once and not keep this up while we don't know what it means?

I am not here to argue global warming/climate change/well maybe

Apex, there are so many different theories about global warming/climate change it is extremely difficult to know which one speaks to the issue correctly. A lot of it depends on your politics, sadly. Many people believe (or do not believe) there is a global warming problem/climate change problem based on their political dealings. Science argues with itself on it. That is why I posted the link I posted.

I do know that CO2 is taken out of our atmosphere by plant life that, for lack of a better term, filters it and regenerates O2, or oxygen that we breathe. What affect has the cutting of the forests around the world had on that? I read recently that over 20% of the world's oxygen in the air comes from the rainforests in Africa. That is being cut down at an exponential rate.

Yes, I know that industrial production and emission of CO2 has also grown exponentially over the years as well. There is more to this equation than what is being presented to us, in my considered opinion. I am NOT for the impending Cap and Trade bill for this reason until there is some kind of legitimate agreement first of all whether or not "global warming/climate change" is a real problem and second having some kind of resolution as to whether or not industrial production and auto emmissions and so forth are a major cause of it.

To me, I'm taking a wait-and-see stance.

Oh, and yes, I know that is not a particularly popular point of view here on BlueNC, so if you argue it, you will most certainly get support from most of the posters here. :)

Why not advocate caution?

I am not arguing global warming either. As I said, way too much dogma going on.


I disagree with this stance on a basic level. I think that we know that CO2 levels are on the increase and that human activities, be they destruction of the forests or industrial emissions, are the major cause. We should stop or certainly limit doing that until we have a better idea about the long term impact it will have.

We only have one atmosphere. Whether you believe it was divinely created this way or our entire ecosystem evolved in concert with a specific composition, isn't it really more sensible to keep it the way it was rather than change it without knowing what that could mean?

Too often have we as a species acted first and considered the implications later. I am not sure that we will ever change, but to me, this isn't an issue of global warming, it is an issue of how we view ourselves as either a part of the planet or apart from it.

It's a good response

I agree that we most certainly should take human causes out of the equation, of course, if it can be determined that it is causing the problems some are advocating.

But, I am suspicious about this "Cap and Trade" bill/initiative. On the surface, it appears that it will be a bill that will help reduce greenhouse gasses but the truth is, a lot of it is conjecture. There are legitimate arguments as to its effectiveness. And, of course, there's the cost. What are the estimates of how much it will cost the average citizen in the increases in power bills? Yes, we can ask "what kind of cost can we put on having clean air", but that seems to be more rhetoric than anything.

I say we take the time to analyze things before we go off half-cocked, so to speak. It is just too important not to do that.

Cap and Trade

If you have a minute, read this:

Cap and Trade isn't a new idea and when applied to a previous air quality issue, it was not only very effective in getting the desired results, but also very cost effective.

This isn't to say that I think that Cap and Trade is the answer. In many ways it is just another case of the government playing favorites and paying them with out money.

I find it interesting that you say:


That is how I feel about the issue of CO2 levels. Before we go off and screw things up beyond repair, shouldn't we analyze things? It really is too important not to.

This part of your post is not accurate

Science argues with itself on it.

Hundreds of peer reviewed research papers have been published supporting the idea of human caused climate change/global warming. If you can find 1 peer reviewed article refuting human caused cc/gw, I'd like to know.

The notion that this there is some kind of debate on this is typical of right wing "muddy the water" tactics.

I actively oppose gerrymandering. Do you?

Oh, my goodness persondem

I didn't present that from some "peer reviewed" kinda thing. It's nonsensical to try to quantify this from one kind of perspective or narrow point of view.

I'm not saying I disagree or agree with one side or the other. You are taking me wrong. I just presented a perspective I picked up that is different from the Al Gore perspective. Climate change and global warming needs to have a look-see, no doubt. No need to get thin-skinned about it, my man.

I presented a link that shows just another view. That's just another view...nothing more. Science does argue with science on this issue. I'm not trying to start some kind of argument or pro/con discussion about it here. Oh, and trust me, I am not presenting this from some kind of right wing philosophy. Isn't me.

But that is how science works ...

Through the peer review process. It is accurate to say that there are differing viewpoints on the topic, no doubt. But to say that there is debate within science is not accurate.
I do not think you are willfully promulgating a right wing agenda, but perhaps have been influenced by the reptitious pseudo-science out there on this topic. From your previous posts, you do seem a sensible sort of person (not that you need me to say so).

iirc the first testimony presented to Congress on GW/CC was over 20 years ago (1986?). Scientists noticed elevated CO2 in the 50's. How much analyzing needs to happen before we realize there's a problem and act to correct it? Perhaps you are familiar with the frog and the boiling water demo?

I actively oppose gerrymandering. Do you?

Let's not become enemies here, persondem

Look, any search on Google or or Bing will show that there are a kazillion differing views on GW/CC. All have their merits...most have their questions.

I'm not a "Cap and Trade" guy because of the costs and because of the questions as to whether or not this legislation will have a significant impact on a problem that is somewhat in question.

You believe differently, persondem. I respect that. I guess we should "agree to disagree" on some of the areas we see differently.

Thanks, my man.

We're on the same wavelength Apex

I guess we can banter this around forever here on BlueNC, but the powers to be will do what they do, regardless, think?

What I dislike about many issues of the day is that our "leaders" seem to make decisions based more on political considerations than good old fashioned common sense and what is best for America and that comes from BOTH parties.

Seems I've opened up a can of worms here !!

I thought I might. HAHAHAHAHA...okay guys, remember that unless we question things, we're just "following along", right?

Okay, fine then

But, if we are, in fact, making "messes", then can we get the collective braintrust in our country together to come up with ways to "clean it up" without costing us an arm and a leg?

Just a thought.

Think of it this way

These messes have been made over many, many generations. There's nothing special about our generation beyond the fact that some of us (baby boomers) are part of a population explosion that was fundamentally unsustainable. We should have been paying the piper all along, but we weren't. We (the collective "we") were too busy making money and making "progress" to worry about a little old problem like poisoning our air, our water ... and our food chain. Trillions and trillions of dollars in profits have been made because companies and people never paid the real costs of their products. By "real costs" I mean the added-in cost of not polluting.

It's hard to imagine that it wouldn't cost billions or trillions of dollars to clean up the damage we've done.

What would it be worth to have a world filled with clean water and clean air instead of a world filled with this?