If you’ve followed the debate over climate change even a little, you likely know the main causes of global warming: concentrations of greenhouse gases build up in the Earth’s atmosphere, and create a “greenhouse,” or warming effect. You’re likely also aware that evidence of past warming periods has fueled the argument that natural causes are largely responsible for current global warming, and thus, our choices of ways to reduce global warming are limited. If Nature’s calling the shots, is there any reason to change human activities that increase levels of carbon dioxide, methane, and other greenhouse gases?
While arguments persist, there’s little doubt that human-produced greenhouse gas emissions play a major role in the current warming trend. Nature has a role, but it pales in the face of increasing emissions from human activity.
What are some of the natural causes of global warming?
Think back to science classes from school. You undoubtedly learned at some point that carbon dioxide is a naturally-occurring compound, that it provides food for plant life, and that animals breathe it out. You may have also learned that decaying organic material releases CO2. There’s no need to question these facts. Greenhouse gases can be emitted into the atmosphere from a variety of natural sources.
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Skeptics of climate science, however, have latched onto a number of natural phenomena, and attempted to argue that they’re primary global warming causes. Some of the natural occurrences you may have heard discussed include:
Volcanic eruptions: Yes, volcanoes emit CO2 when they erupt; as Grist’s Coby Beck showed, though, volcanic CO2 emissions do not outweigh those produced by humans.
Solar cycles and cosmic rays: If you followed discussions about the causes of global warming at all, you’ve run across this argument. A recent study released by a group of European scientists concluded that “The chance of the natural cosmic-ray or solar irradiance explanation being responsible for more than 14% of the observed warming is quite negligible.”
Water vapor: You may have heard the claim that water vapor’s the most prevelant greenhouse gas, and therefore is the main cause of global warming (not CO2). This is half true. Water vapor is the most prevalent gas; however, it’s produced as feedback of increased CO2 emissions, and is not a “forcing” of global warming.
Why human causes of global warming are a much bigger problem
Many of the activities you take for granted ultimately contribute to global warming, including
- Driving your car
- Turning on your air conditioning or heat
- Eating food that is locally out of season (or not locally grown), and shipped from other parts of the country or world
All of these activities rely on the use of fossil fuels. Burning of these fuels releases carbon dioxide… but CO2 that exists in a very different part of the carbon cycle. Fossil fuels are sequestered carbon: the elemental remains of organic entities (plants, animals) that were “stored away” by natural systems in order to maintain stability in the climate. You may find it ironic that many scientists and engineers are searching for ways to sequester carbon emissions: Nature had already done it quite well!
When you release carbon from fossil fuels by burning them, you’re essentially contributing to an “overflow” of greenhouse gases in the atmosphere. This overabundance of heat-trapping gases can lead to:
- Rising sea levels
- Changes in seasonal weather and precipitation patterns
- Increased severe weather effects
- Lower rivers and lakes that are fed by snow and ice melt-off
- Habitat changes for a wide variety of plants and animals
So, can you claim a straight-line, cause-and-effect relationship between climate change and these phenomena? No… but we do know that climate change increases the probability of these effects. Consider Colorado University climate scientist Brad Udall’s analogy: the climate is like a six-sided die, with “Two faces [that] say warm, two normal, two cold. That is your normal climate… We have now changed it. Now it says three warm, two normal and one cold.” “Rolling the die” becomes much more treacherous.
Do natural events and occurrences play a role in global warming? Definitely. But if we’ve learned anything from studying the geological record, it’s that nature’s time table is very different from the one for the current warming cycle — the climate has never warmed at this quick a pace. We also know that extreme climate changes produce extreme results for life on Earth… and that you want to do your part to ensure that such results don’t occur more quickly than they might otherwise.
If you’re looking for more detailed scientific information about the evidence for human-caused climate change, check out the International Panel on Climate Change’s “Summary for Policymakers” of its Fourth Assessment Report.
Image credits: takomabibelot and flydime at Flickr under a Creative Commons license
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I think it’s obvious that Humans are causing a lot more damage to the environment than anything natural.
Just like the above ideas pointed out, the technology is outdated.
It’s good that more businesses are trying to go green than ever before, but it’s gonna require more than that.
Great Post!
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Chris
Alternative Green Technologies
Green Technology Blog
Since 2000, atmospheric carbon dioxide has increased 18.4% of the increase from 1800 to 2000. According to the average of the five reporting agencies, the trend of average global temperatures since 1998 shows no increase and from 2002 through 2008 the trend shows a DECREASE of 1.8°C/century. This separation (there have been many others) corroborates the lack of connection between atmospheric carbon dioxide increase and average global temperature.
Many Climate Scientists appear to be completely uninformed of some relevant science and understand other relevant science poorly (it’s not in their curriculum). The missing science, using paleo temperature data, proves that added atmospheric carbon dioxide has no significant influence on average global temperature. See the pdfs linked from http://climaterealists.com/index.php?tid=145&linkbox=true for the proof, to identify the missing science and to see the cause of the temperature run-up in the late 20th century. Climate Scientists have adopted the word ‘feedback’ but use it completely differently than had been successfully applied for decades by engineers.
As the atmospheric carbon dioxide level continues to increase and the average global temperature doesn’t it is becoming more and more apparent that many climate scientists have made an egregious mistake and a whole lot of people have been misled.
By its very nature, climate changes. The climate on earth has ALWAYS CHANGED and will continue to CHANGE, no matter what we do.
Those brainwashed to the point of wanting to destroy the economy to “prevent global warming” are behaving like the most primitive human beings who were duped into believing that human sacrifices would ensure them good weather. Human beings don’t have the power to control climate! And killing the economy will not help the environment.
We have to acknowledging how insignificant we humans are in comparison to the natural forces that have been influencing this earth for millions of years
Global warming the greatest hoax ever perpetuated on the American people and the world. It is a scare tactic. Global warming is a phrase that should be always retired from the climate debate.
Please read this:
http://www.geocraft.com/WVFossils/ice_ages.html
It is so strange that those who believe scientists when they find
that germs cause disease,
that asteroids if headed this way would be dangerous,
that atom bombs cause cancer,
that ozone holes cause melanoma,
that overeating causes obesity,
that reading in the dark causes eyestrain,
that pollen and pollution causes asthma
and so on and yet….
suddenly pull up short when scientists find that carbon emissions cause climate change!
Yet nearly all of those simple problems scientists uncovered were (once uncovered) easily able to be solved by other scientists,(and doctors,and soap manufacturers and Asthma inhaler manufacturers staff scientists and Jenny Craig, etc, etc)
In the same way the simple problem of climate change from carbon emissions can be (and will be) solved by the thinking of automobile designers and mechanical engineers and architects, etc.
On second thoughts, maybe the people who can’t believe scientists on climate change also don’t buy science on how “germs cause diseases” either?
Maybe you are still at the “gravity causes apples to drop from trees to the ground” stage of scientific cause and effect thinking?
14th century science?
Susan,
Those who understand ALL of the relevant science know that added atmospheric carbon dioxide does not significantly increase average global temperature. The issue exists because Climate Scientists appear to be unaware of the science that disproves AGW (as I said above, it is not in their curriculum).
Let’s get real. Climate change is indisputable. The human influence on climate change is disputable. Oil, gas and coal have provided us with one of the greatest runs of social and scientific advancements in human history, but they’re all finite. Cheap energy is the only thing that has allowed these advances and there is nowhere in the world these resources will be easier to extract than the resources that have already been recovered. It is taking more energy to get every gallon of oil, cubic foot of gas, and ton of coal out of the ground today than it did 10 years ago and it’s only going to continue until the ratio approaches one to one.
We need to stop being so damn altruistic in our attempts to save the planet and get selfish and start saving ourselves. Our food supply is completely dependent on non-renewable energy. Natural gas makes the fertilizers, diesel runs the trucks and tractors, oil makes the pesticides, and coal & gas is responsible for the processing, refrigeration, and heating of our food. The only way to save ourselves is to put in our own sweat equity to secure our own food that is independent of the grid.
Stop focusing on your neighbor’s SUV. Let that be their problem when gas climbs over $5/gallon. Focus on your own ability to survive and perhaps even thrive the coming crisis when the oil stops flowing. You’ll not only save yourself, but you just might put a little less CO2 in the atmosphere while you’re at it.
@Jeff
The statistics that you cite(can you call the denialist blog you link to a citation?) to make your point have been addressed too many numerous times by climate scientists for me to bother trying to argue them here. Google is your friend, as are peer-reviewed publications. Denial-blogs written by wonks are not valid sources of information, sir. The fact remains: you are in an incredible and noncredible position. It doesn’t matter how angry that makes you, or how unfair you may think it is, AGW is a fact, and it’s not going away, no matter how much spurious nonsense you spout on these blog posts.
@Jeff McIntire-Strasburg (author)
May I humbly suggest that you change the title of this blog post so as to not indicate that there is valid scientific debate whether AGW causes are human or not? It is now conclusive–beyond a reasonable doubt–that AGW is real, and that the anthropogenic aspect of the theory is well-backed with real, and mounting data. By casting the title of your post as such a question, you are baiting the denialists and contributing to further public confusion over whether there really is a debate or not. There is no debate. The question in your title has been answered, and the only reason to pose the question at this point is to drive troll traffic to your site (see comments above).
I would also humbly request that you change any references to “sceptics” of AGW in your post to “denialists.” People who continue to buy into the conspiracy theories that AGW is a hoax or that it’s not caused by humans are not skeptical; they are deniers. To call them skeptical misinterprets the very definfition of what a skeptic is, and further adds legitimacy to the wack-jobs and their insane ranting.
rockymtnway,
All true except for the bit about CO2. Added atmospheric CO2 has no significant effect on climate but has increased food production.
With the existing known technology of nuclear fission and breeder reactors, all of the energy needs of humanity can be met for millions of years. Generated electricity could provide light, heat and mechanical power for homes and commercial customers plus 80% of personal transportation energy by using plug-in hybrids. The energy could also be used to synthesize liquid fuel for the other 20% of personal transportation. This will eventually need to happen.
@Allan–
Thanks for chiming in. I agree with your premise that the debate is over, but disagree with the idea that the title “is baiting denialists” (or only doing that). Unfortunately, the waters have been muddied, and there are still plenty of people asking that very question that want answers based in science… I think the post addresses that.
As far as “skeptics” vs “deniers” — I think we spend way too much time on those kinds of arguments. If being a little generous with my labels avoids arguments on those labels, and keeps us focused on showing people in the middle the scientific facts surrounding climate change, I’m OK with being a bit generous… Moderation of tone doesn’t mean that I’m not passionate or serious about these issues; it means I recognize that some people who are still trying to figure all of this out get turned off quickly by a strident tone…
Again, thanks for your input… I understand completely where you’re coming from…
Climate Scientists have calculated that increased atmospheric temperature causes increased water vapor in the atmosphere which further increases temperature. That is, that there is a positive feedback from temperature caused by increased water vapor in the atmosphere. Climate Scientists have calculated that other phenomena also contribute to temperature feedback. They combine all of these factors that they know about and get a NET positive feedback from temperature. With a NET positive feedback from temperature, their climate models will always show a continuation of a rising temperature trend.
If a NET positive feedback from temperature were true, then a rising average global temperature trend could never change direction and become a declining temperature trend and/or vice versa. A review of accepted temperature anomaly data from the last (and previous) glacial periods reveals multiple examples of where temperature trend direction change occurred. This could only occur if there were no significant net positive feedback from average global temperature. Thus contrary to the popular ‘consensus’ of Climate Scientists there is no significant NET positive feedback from temperature.
There must be negative feedbacks (as yet undiscovered except for Lindzen’s Iris Effect which alone may be adequate) that, when combined with the positive feedbacks from water vapor, etc., results in the NET feedback from temperature being not significantly positive. Without NET positive feedback the Global Climate models predict that there will be NO significant Global Warming from doubling atmospheric carbon dioxide. Without significant Global Warming from increased carbon dioxide, human use of fossil fuels has no significant influence on climate. Details and graphs are available at http://climaterealists.com/index.php?tid=145&linkbox=true . Any action that is taken to reduce human produced carbon dioxide to reduce global warming or influence climate is a mistake that puts freedom and prosperity at risk.
The fundimental question is not about the alternative explanations for Global Warming. The critical issue is that AGW is a theory based solely on a crude computer model of the environment. It may be indisputable that CO2 is a greenhouse gas, what is not know is how significant is its effect. Even the GCM – global climate model depends on feedback effects – basically CO2 alone does not produce the desired results. This is not established science, it is political science. Even the politically corrupt IPCC report does not support the fear mongering of the AGW malthusians. The opponents of AGW are increasing rather than decreasing. The include an increasing number of renowned scientists.
Rant all you want about deniers, the GCM fails the most simple test. Outside the 20 year window ending with the turn of the century its predictions are completely off base. It does not accurately represent the past prior to the late 70’s, nor has it been accurate since 1998. We may have gained a great deal of knowledge over the past 30 years, but the fact is we do not know what causes climate change. You are absolutely correct that current science can not attribute Global warming to solar changes. At the same time models presuming climate change is entirely solar are orders of magnitude more accurate than CO2 models. Which do you want to bet on ? A model that works that requires the effects of the sign to be much greater than we beleive they are, or one that does not work and requires the effects of CO2 to be much greater than we know they are.
“All of these activities rely on the use of fossil fuels…Fossil fuels are sequestered carbon: the elemental remains of organic entities (plants, animals) that were “stored away” by natural systems in order to maintain stability in the climate.”
Even the supposedly settled scientific statement regarding “dino-fuels” can be called into question, because it fails to account for similar compounds found on the lifeless planets within our own solar system. Some places apparently have fossil fuels minus the fossils. How in the heck did that happen?
Also, if the planet sequestered carbon by generating oil and natural gases to maintain pre-industrial climate stability, how do we know that it lacks the ability to use the same mechanism in this industrial age?
It takes some effort, but it is possible to argue Dan Pangburn to a standstill. In the end, his theory that sunspots are causing climate change is indefensible.
See: http://www.sindark.com/2009/07/28/hfcs-and-climate-change/
If animals breathe out CO2 and if that is what causes the infamous greenhouse effect, tehn it seems to me that it is humanity which has increased by billions that is causing global warming.
Jeff, I just read this old post. You must realize that your list does not really touch on the “top” causes. Non-local food definitely would not be on that list. Since this still comes up all the time on you most visited links, wouldn’t it make sense to put a little more rigor into the analysis?
Steve
Thanks for this post. I am trying to understand global warming better. I think I am a long way away, but this is a good place to start.
I tend to trust a scientific consensus, but I am approaching the matter with skepticism so that I can ask the right questions and gain a better understanding.
I am sure that you would not disagree that the earth has gone through and continues to go through many significant climate changes over the last billion years.
Please explain how the current climate change is different and please tell me how any change we make today can stop the global climate change in any way.
I remember during the 1960’s when environmentalists were yelling about the coming ice age due to man’s interference with the environment. “We’ll no longer see blue skies after the 1970’s”, or “Ice will be common as far south as the northern US by the 1990’s”. Obviously nothing happened. 40 years later and the alarmists are yelling about global warming. These are CYCLES of nature that occur over thousands of years, not hundreds. It’s more political than environmental and that’s the bottom line.
People need to realize the earth has been going through extreme changes long before we had cars and were burning fossil fuels. Everyday all day every human EXHALEs CO2. So are we going to limit our breathing?
If man is the cause of global warming then…
HOW DID ALL THE SNOW AND ICE FROM THE ICE AGE MELT AWAY?????
I think scientists and the world doesnt really understand global climate change and what is the real cause of it. Climate change has to be natural and nothing humans do will make any difference at all to the temp on earth – evan is right. Scientists blame humans and greenhouse gasses because they dont really understand earth and the sun and how it affects rising temp. There are no greenhouse gasses in the antartic where all the icebergs are melting away so how can humans be causing the ice bergs to melt. There is only one thing that can melt the icebergs and increase the temperature on earth and thats natural changes and changes in the sun causing an increase in heat from the sun. Look at the gobshite who invented the hockey stick that proves scientists havent a clue.
I’ve given a lot of thought and study to global warming over quite a fewyears. I have an M.S. in counseling psychology, and one of the conclusions I’ve come to is that people who are still denying global warming is both real and human-caused may have a form of mental illness. I explain this further here: http://www.diamondcutlife.org/the-psychology-of-naysayers-on-global-warming/
I think this is a very good website because i am doing an assignment about climate change, and I got alot of my information from this website.