Top Global Warming Causes - Natural or Human?
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.
- » See also: Revenge of the Angry Mermaid
- » Get Sustainablog by RSS or sign up by email.
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
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!
-
Chris
Alternative Green Technologies
Green Technology Blog
[...] gas emissions, especially carbon dioxide. You may not, however, be aware of some other major global warming causes that you encounter regularly. For [...]
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.
[...] thanked European citizens who’d participated in months of non-violent direct action on the causes of global warming, and noted this activism had resulted in the political will to address climate change in a [...]
@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.