How Could We Affect The Earth?

Posted by Ethan on April 24, 2009
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As many of you have heard, the Earth has been getting warmer, rapidly, since the industrial revolution. And as many of you have also heard, there is, historically, a link between greenhouse gases and temperature here on the Earth.

So, with Earth Day just behind us, I thought of a little analogy for the one question I hear more than any other about global warming:

How could something as small as a human being affect the climate/temperature of the entire Earth?

The analogy is good old-fashioned water torture. What harm can one drop of water do to you? Pretty much nothing, of course. But what if you randomly dripped cold water on the same exact spot for hours or even days on end? The result is that the victim can go insane (as confirmed by mythbusters) from this. It’s because a cumulative effect, over a long period of time, can be significant even for a small thing.

But this is Scienceblogs, and I’m a scientist. We don’t reason by analogy here except for help in explaining. Instead, if we want to test something, we do the science. So let’s take a look at what we’ve been doing to the Earth. The United States, right now, is responsible for between 20 and 25% of the greenhouse gas emissions in the world, most of which is carbon dioxide. Check out the latest (2007) statistics:

That’s a lot of gas, but surely it’s insignificant compared with the entire Earth’s atmosphere! And, of course, it is. The mass of the entire Earth’s atmosphere is somewhere between 5,000 and 5,300 trillion metric tonnes and so this 6 billion metric tonnes that we put out could hardly ruin the planet, right? Well, we’re not the only country on Earth, but moreover, 2006/7 wasn’t the only time we put large amounts of carbon dioxide into the atmosphere. Take a look at the long-term statistics of carbon dioxide released from fossil fuels.

Well, doing the math on these statistics, from 1800 to 1950, the world’s human population released 300 billion tonnes of carbon dioxide into the atmosphere. You’ll notice that, because this was such a (relatively) small amount released over a (relatively) long time, the effect on carbon dioxide concentration wasn’t very pronounced.

But over the next 30 years, from 1950-1980, we really ramped up out fossil fuel consumption, and over those 30 years we put out 390 billion tonnes — more than the past 150 years — in just 3 decades. You’ll notice that the rise in carbon dioxide concentration over that time is pretty steep.

And as for the last 29 years, from 1980-2009? We’ve put out more fossil fuels than ever before: an unprecedented 725 billion tonnes over that timespan. So what does all of this mean for our atmosphere? Could humanity — a few billion tiny animals — really affect the entire atmosphere of our planet?

Well, our 5.3 trillion tonne atmosphere is made up of the following:

  1. Molecular Nitrogen — 78.08%
  2. Molecular Oxygen — 20.95%
  3. Monatomic Argon — 0.93%
  4. Other — 0.04%

Nitrogen, oxygen, argon, and a little bit of other stuff. How bad could adding this carbon dioxide to the atmosphere be? (Aside from killing the great barrier reef, of course.)

Well, add those numbers above up, and you’ll find that we’ve added more than 1.4 trillion metric tonnes of carbon dioxide to the atmosphere over the past two centuries. Using the most recently measured figures, how many tonnes of carbon dioxide are in our atmosphere now? Just over 2.0 trillion. The Earth has “processed” (i.e., managed to deal with and remove from the atmosphere) some of this carbon dioxide, but not nearly enough of it, and not nearly quickly enough.

Keeping with the current trends, we will have double the amount of carbon dioxide in our atmosphere by 2040 than we did in 1800, and this carbon dioxide is forcing the temperature increases we’re seeing now. Whether you’re convinced by this convincing evidence that has convinced climate scientists for decades or not doesn’t matter. What matters is that we have hundreds of billions of tonnes of extra carbon dioxide in our atmosphere, with no known way to deal with it.

The least we can do is stop making it worse, which means to stop burning fossil fuels, or — at the very least — to burn as little as possible as slowly as possible. And that’s my concluding thoughts to you this Earth Week!

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Comments

  1. #1 NewEnglandBob
    April 24, 2009

    Pretty convincing. Unfortunately most people have the attention span of a gnat and would not get through reading your post.

  2. #2 Ethan Siegel
    April 24, 2009

    Sorry if it was long-winded! I tried to break it up with pictures; perhaps next time I’ll try to keep it briefer.

  3. #3 Xanthippas
    April 24, 2009

    I’ve yet to read anything as “simple” and compelling as this on how it’s possible for mankind to have such an impact on the climate. Even global warming deniers can handle addition, and the math here is hard to argue with. Thanks.

  4. #4 Curious...
    April 24, 2009

    When it comes to global warming, I put myself firmly in the “I don’t know” category. One thing that strikes me about that first graph, though, is that it appears that CO2 and temperature spike every hundred thousand years or so and then fall gradually, and it appears we’re right on course for a spike. I’m curious about what the current theories are on the previous spikes.

  5. #5 Glendon Mellow
    April 24, 2009

    I didn’t find that too long at all. Clearly explained, step by step and broken up with colourful pictures and graphs. Great post.

    There’s a gnat sitting next to me nodding in agreement.

  6. #6 mus
    April 24, 2009

    I didn’t find it long either, I think this length is great.

    While we’re talking about analogies, I like to bring up fog whenever people say that the amount of CO2 in the atmosphere is insignificant. The concentrations of CO2 are usually measured in parts per thousand (or million, whatever), not in absolute terms. This is like saying that from here to your hand there is so much fog, but that doesn’t give you a very good feel for what the effects are. If you multiply that small amount of fog (or CO2) by kilometers, even a very slight change in the concentration can have huge effects. Add just a little more fog per unit of length, and the visibility drops a whole lot. Same with CO2… add a little more per unit of measurement, and it traps a whole lot more heat given that it is multiplied by the whole atmosphere.

  7. #7 Richard Simons
    April 24, 2009

    Curious . . says

    “. . it appears that CO2 and temperature spike every hundred thousand years or so and then fall gradually, and it appears we’re right on course for a spike. I’m curious about what the current theories are on the previous spikes.”

    I am not a climatologist, but my understanding is that the previous rapid increases in CO2 were a result of regular cyclical changes in Earth’s orbit warming the oceans, resulting in a release of dissolved CO2, which in turn caused more warming and so on until a new equilibrium was reached. The spike that we were ‘right on course for’ took place about 10,000 years ago, which is one reason why agriculture was able to flourish.

    The current concentration of CO2 in the atmosphere is well off the graph. It should be shown somewhere around the ‘industrial’ in the opening paragraph.

  8. #8 Raimund
    April 24, 2009

    Another great post! Your use of pictures is always fantastic. Personally I’m in a somewhere between the camps camp on the climate change issue. I’ve heard reports that downplay the accuracy of the climate models as well as plenty of reports that strongly show the case, and not being an expert in the matter my personal feelings or intuitions aren’t very important in any way. I do very much agree though that a rapid change in the atmosphere must lead to changes in the earth’s dynamic systems in very unpredictable ways and that what we see in the geological record of such things indicates hard times. But what we also see after extinction events such as at the Permian or K/T boundaries is a blossoming of new and innovative changes in life, and a part of me can’t help but feel that however the world changes in the short-term, the long-term changes will make very effective use of the new conditions. I can’t honestly say that I’m worried for the overall welfare of the earth either, besides that I’m pretty happy with things as they are right now, and it’s not too hard for me to imagine that in a distant future these changes now might be considered as a bit of a godsend.

    Ok, so that makes me sound like I support the continued use of fossil fuels, but in reality I don’t. Besides everything else, it’s high time for a new economic driving force, and it seems to me that using what we know to promote a better integration of technology and ecology is a pretty good idea.

  9. #9 Dave Hodgkinson
    April 25, 2009

    Lovely graphs, nice prose and very clear.

    But all you’ve done is illustrate the correlation.

    How does the science work? What does more CO2 in the atmosphere *do*?

  10. #10 NewEnglandBob
    April 25, 2009

    Ethan, I wasn’t complaining about the length of this terrific article, I was just pointing out a sad fact of American life.

  11. #11 george.w
    April 25, 2009

    Awesome post, bookmarked and will be referred to as a resource.

    Hope you wouldn’t mind another analogy – I’ve been using this one for a few years:

    A termite weighs about 2.5 milligrams. A typical house weighs something like 60 tonnes, or about 24 billion times as much as a termite. How can puny little termites do any real damage to anything as massive as your house?

    Answer: a lot of termites, each doing a little bit of damage at a time. And no, we’re not different from termites; we’re living things that consume resources and produce waste. Even termites, tiny as they are, produce enough methane to contribute measureably to global warming, though their production has been stable for a long, long time. They have not learned to dig gigatonnes of coal out of the ground and burn it.

  12. #12 george.w
    April 25, 2009

    Oops, I made some mistake in the HTML there. Sorry.

  13. #13 Sili
    April 26, 2009

    Even if we were at the cusp of a natural variation (not that we are – my impression is that the long term cycles have to do with Earth’s precession; there are bigger landmasses in the North, thus it make a difference is the Northern Summer falls near perihelion or aphelion (as it does now)), wouldn’t that just be further incentive to get rid of the human component?

    Look at the graph: we burn fossil fuels, CO2 is released into the atmosphere – this cumulative release fits the increase in overall concentration. If you want to say that the CO2 has a natural origin you have to explain what happened to the tonnes we’ve released.

    CO2 absorbs infrared radition from the ground. And then reëmits it randomly. Thus energy that would otherwise return to space is redirected back towards Earth. The more CO2 the more radiation can be retained. Keep in more energy and the temperature rises – like under the duvet on a cold night.

    In both cases we know the effects. Anyone who wants to come up with a different explanation (cosmic rays, sunspots, volcanoes) not only have to muster some evidence for their favoured idea, but they have to dismantle the mountains of evidence for the concensus as well.

  14. #14 Mike K
    April 27, 2009

    “One thing that strikes me about that first graph, though, is that it appears that CO2 and temperature spike every hundred thousand years or so and then fall gradually, and it appears we’re right on course for a spike. I’m curious about what the current theories are on the previous spikes.”

    The previous spikes are the “natural cycles” you hear about so much from skeptics. What they fail to mention is that the current cycle ISN’T natural. WE are causing the current spike, it’s obviously an exponential rise (something that also hasn’t happened naturally in the past), and it shows no signs of slowing or stopping – quite the opposite, it is rising. We’ve poured more C02 into our atmosphere in the last 30 years than in the previous 180, and that number is going up. And we’re talking about capping emissions at 2005 levels!

    I’m not optimistic that we’re going to pull out of this, not at all. I think it’s good to be skeptical and to question everything (such is the essence of science), but quite frankly in this case, you skeptics are literally killing us.

  15. #15 Lotharloo
    April 27, 2009

    Even the ICPCC doesn’t say for sure that we are causing the global warming. The sceptics can point out all the little mysteries but it should not make a difference in the policies. A lot of scientists are convinced that GW is man-made and it would be stupid gamble that they are wrong. I have no problem with sceptics as long as they agree that it is reasonable to reduce CO2 emissions; if they don’t then it can only mean that they are dogmatically very sure of the correctness of their position.

    (I’m ignoring the fact that there is overwhelming scientific consensus among those who study GW that it is man-made)

  16. #16 Jason A.
    April 27, 2009

    Dave Hodgkinson

    Lovely graphs, nice prose and very clear.

    But all you’ve done is illustrate the correlation.

    How does the science work? What does more CO2 in the atmosphere *do*?

    Simply put, the ground radiates ‘heat’ (infrared light) that would go unhindered up into space and away from earth, except that greenhouse gases like CO2 absorb the heat and re-radiate it in all directions – including back down at the Earth. Heat that would leave is now being trapped here.
    See this image – http://earthobservatory.nasa.gov/Features/GlobalWarming/Images/radiation_budget.jpg
    The part we’re interested in is to the lower right, ‘absorbed by greenhouse gases’ and ‘re-emitted radiation’.

    And yes, the skeptics will say water vapor is a more significant greenhouse gas than CO2. What they fail to see is that water vapor can quickly return to ‘balance’ levels if disturbed. Too much water vapor in the atmosphere and it rains out. Too little and it evaporates up off the oceans.

  17. #17 Jason A.
    April 27, 2009

    damn, blockquote fail. Anyways…

    Curious…:

    When it comes to global warming, I put myself firmly in the “I don’t know” category. One thing that strikes me about that first graph, though, is that it appears that CO2 and temperature spike every hundred thousand years or so and then fall gradually, and it appears we’re right on course for a spike. I’m curious about what the current theories are on the previous spikes.

    While I’m not sure about the causes of the previous spikes, one significant thing to notice is that the previous spikes all topped around 280-300ppm. Today, the concentration is around 380ppm, which is about 35% higher than the peaks we see in the records of natural cycles. In addition, todays concentration is exponentially increasing, so even topping at 400ppm seems wishful thinking.

  18. #18 Dave Hodgkinson
    April 29, 2009

    Thanks Jason A. A couple more questions then:

    1. Is CO2 (and methane) the prime candidate in all this? Are there other issues? Or do things like reduced reflection of heat because of reduced snow, merely follow from this?

    2. Has the effect been effectively demonstrated experimentally? I’d settle for in a lab but preferably somehow demonstrated on a large scale in the wild :)

    One more thing:

    How many trees would we need to plant to capture the carbon emitted in the last few decades?

  19. #19 Ned
    April 29, 2009

    Why is there so much recent data that is indicating a cooling earth?

    Why are there so many scientists with legitimate qualifications that
    don’t support AGW?

    Why is the IPCC mostly bureaucrats & politicians? & those that are scientists, why are so many not actually climate scientists but specialists in unrelated fields?

    Is CO2 really a pollutant?

    When we breath, are we polluting? When all the mammals breath, are they polluting?

    When plants metabolize CO2 into O2 are they feeding on a pollutant?

    What is the proper concentration of CO2 in the atmospehere?

    Could you tell me what temperature is normal also?

  20. #20 Torbjörn Larsson, OM
    May 1, 2009

    Denialists put the stupidest questions out:

    Why are there so many scientists with legitimate qualifications that don’t support AGW?

    That is what they say of the creationist “doubt on evolution” list as well, yet only 2 out of hundreds are actual biologists.

    [And BTW the list is only doubting that natural selection can explain all of evolution, something that actual biologists would underwrite if it wasn't on a religious political agenda, since there are more mechanisms already in the actual theory.]

    But the fact is that the IPCC presents a review of todays climatology.

    Why is the IPCC mostly bureaucrats & politicians?

    Because IPCC is created to inform politicians about the current science. Politicians aren’t scientists that have studied these questions for years and keep up with all the current literature.

    & those that are scientists, why are so many not actually climate scientists but specialists in unrelated fields?

    Because “IPCC assesses the scientific, technical and socio-economic information relevant for the understanding of the risk of human-induced climate change”, so scientists from related (i.e affected) fields must participate.

  21. #21 piratebrido
    May 11, 2009

    I’m guessing that I am being thick, but you first say that “The mass of the entire Earth’s atmosphere is somewhere between 5,000 and 5,300 trillion metric tonnes…” and then you say “Well, our 5.3 trillion tonne atmosphere is made up of the following”

    Which is it, 5,3000 trillion tonnes or 5.3 trillion tonnes? Or am I not getting the metric part?

    By the way, love the blog.

  22. #22 Ethan Siegel
    May 11, 2009

    5,300 Trillion. Sorry for the error in scientific notation!

  23. #23 piratebrido
    May 11, 2009

    Cool. Now I can impress people because I know the mass of the atmosphere of Earth!

  24. #24 Phil
    June 3, 2009

    The regular temperature and CO2 spikes are not entirely our fault. It is nowhere near as many people would lead you to believe. Its really fluctuations in the energy output of the sun due to the unevenness of the sun’s fusion and gravitational pull fighting against each other at all times. When the sun is on a high it is fusing more and pushing out, but then the pressure is too little to fuse and the gravity takes over.

  25. #25 Jay Allison
    October 1, 2009

    Natural Laws are not able to pardon us, for creating carbon dioxide overloads, with our Black Magic Lifestyle. Because we so enjoy the creature comforts we create with the powers of fire, our planet will become as desolate as Mars; much sooner than Nature intended. Weakling humans, that sensationalize encasing ourselves in 4000 pounds of steel, glass, rubber, paint, and plastics, for our ride to the theater, will die off quickly; unable to endure the future harsh consequences of our Black Magic Lifestyle. Our planet is sick, its temperature is rising as it develops a fever to combat an infection.

    We have gained partial control of our living environments now, thanks to life’s 3 billion-year struggle. In cosmological time, life on this planet has only just recently crawled out of the primordial mud from which it arose. Because we are a young species, human greed, the need for conformity to beliefs, and the ostracism of diversity, is apprehensible.

    Humans are now poised to fail, reversing the tenacious advance of life, and fall; back into the proverbial mud. We will only survive global warming long enough to experience the comparatively mild beginnings of the permanent damage our species caused, to the one of a kind space ship that all life shares, our biosphere. We will stifle and perish, along with all the other higher life forms. Humans have created conditions that humans can not survive. We blame and evade our own personal responsibility for this imminent disaster, rather than avoid it, by demanding the development and implementation of plans and processes to accomplish the removal of the excess atmospheric and oceanic carbon dioxide, we created. As in driving over a cliff, just slowing down will not avoid the eventual fall, we must reverse global warming. Without our demands for better, the answer to global warming, will be a nuclear winter.< <

    Destruction of the natural environment by humans will end, here on this dying planet, as we create our own hideous extinction. Our love of power, strife, and conquest, will not spread throughout the galaxies.

    The Universe will be left in peace. . . once again.

  26. #26 Liam Z
    April 28, 2010

    This was a great post. It wasn’t too long at all. Great use of pictures and good analogies.

  27. #27 Deltron
    March 26, 2011

    The regular temperature and CO2 spikes are not entirely our fault. It is nowhere near as many people would lead you to believe. Its really fluctuations in the energy output of the sun due to the unevenness of the sun’s fusion and gravitational pull fighting against each other at all times. When the sun is on a high it is fusing more and pushing out, but then the pressure is too little to fuse and the gravity takes over.

  28. #28 Deltron
    March 26, 2011

    Natural Laws are not able to pardon us, for creating carbon dioxide overloads, with our Black Magic Lifestyle. Because we so enjoy the creature comforts we create with the powers of fire, our planet will become as desolate as Mars; much sooner than Nature intended. According to weathercast forecaster Weakling humans, that sensationalize encasing ourselves in 4000 pounds of steel, glass, rubber, paint, and plastics, for our ride to the theater, will die off quickly; unable to endure the future harsh consequences of our Black Magic Lifestyle. Our planet is sick, its temperature is rising as it develops a fever to combat an infection.

  29. #29 Msud Ahmed Sanzu
    February 19, 2012

    Bangladesh is one of the most severest Carbon emission country. Now try to think how to response the issue. forestation, water lands, cultivating fields are vulnerable to the occupiers and unplanned infrastructures. As well as wild live are at the brink of extinction.

  30. #30 bobby
    April 24, 2012

    this is very gooooooood

  31. #31 tony
    April 24, 2012

    this did nit help at all with my homework

  32. #32 Sam
    Pennsylvania
    February 9, 2014

    yeah really it was well written and a good length, but it did nothing for my homework