Arguments
Are humans too insignificant to affect global climate?
What the science says...
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Humans are small but powerful, and human CO2 emissions are causing global warming. |
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Climate Myth...
Humans are too insignificant to affect global climate
To suggest that humanity is capable of impacting and disturbing forces of such magnitude is reflective of a self-centred arrogance that is mind numbing. Humanity is a subset of Nature. Nature is not a subset of humanity. We have travelled full circle. We are back in the mindset that prevailed when Society’s leaders dictated what people in Copernicus’ days may or may not think. The Earth is once again flat. (source: Financial Sense University)
When we experience weather events like hurricanes and floods, it’s very easy for us to feel insignificant and powerless in the face of such massive natural forces. How can humans influence this? Well, yes, we can. Of course we can’t influence a single weather event, but we can and do have a long term influence on the climate that causes it.
Since the industrial revolution, with ever-increasing supplies of fossil fuels, the activities of a dramatically expanding world population have made significant alterations to the make-up of our atmosphere.
In some cases human-caused change is direct and unambiguous. The harmful effect of the human release of CFCs on the ozone layer is well documented and not disputed. Down on the ground, draining of marshland and deforestation can produce a significant decrease in water vapour in the atmosphere downwind; while the introduction of irrigation for agriculture has the opposite effect. Over time, both of these human activities can alter patterns of rainfall, turning deserts into green areas and green areas into deserts.
In other cases the human causes of climate change are more complex. Emissions from cement production, pollution and the release of particulates to form smog in the atmosphere, all affect climate.
Without doubt the most significant of all the human causes of changing climate is the dramatic increase in CO2. After remaining relatively steady for the last 650,000 years or more, in just the last two hundred years the concentration of CO2 in the atmosphere has suddenly shot up from 280, to more than 380 parts per million. And it’s still rising. This dramatic 30% increase has all taken place at the same time as humans have been burning fossil fuels at a greater and greater rate.
Of course there are also natural sources of the CO2 in the atmosphere, such as vegetation, but fortunately there are differences that scientists can measure between the CO2 derived from fossil fuels and the CO2 derived from plants. The changing concentrations of the two types demonstrate that the additional CO2 can only be the result of human activity.
This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)
Of course, as CO2 is the most common of greenhouse gasses, the additional concentration is what causes most of the rise in temperature. This is resulting in a change in weather patterns and ocean currents; the melting of global ice formations; and an increase in extreme weather events.
So, yes; though we might be pretty helpless when it comes to controlling the weather, humans are certainly capable of changing the world’s climate.
Basic rebuttal written by John Russell
Update July 2015:
Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial
Last updated on 30 November 2015 by MichaelK. View Archives
But I agree, buying electric cars and more efficient lightbulbs are only a tiny drop, to borrow your metaphor, compared to the effort required to lower and eventually stop CO2 emissions.
Sure, humans don't have the ability to seriously harm life on earth, and the Cold War was really about the rise of polar bear batallions.
Everyone seems to agree that if we follow the present trend, by the end of the century the temperture of the planet will increase by 4 degrees. Your article shows that at worst case the human cause is 1%. So 1% of 4 degrees is only 0.04 degrees. When you factor in all of the other variables your article mentions, plus forest fires, volcanos, etc., if all human causes were removed, there would be no noticable affect on the temperature even considering your water vapor loop which is present and obviously included in the 4 degrees change.
[PS] "Your article shows that at worst case the human cause is 1%" This does not follow from the article at all. Can you please be more explicit where in our article that you get the idea that long term change in temperature (as opposed to short term variations) is only 1% human? We obviously need to improve clarity. AR5 put it at more like 110% (the earth would be cooler without anthropogenic effects). Discussed here.
Denny @21, as the moderator [PS] indicates, the IPCC AR5 found that in the period 1951-2010, more than 100% of warming was due to anthropogenic factors, as shown in this graph derived from AR5 data by Real Climate:
The likelihood that anthropogenic factors caused only 50% or less of the warming is very small (0.06%) based on that graph, while the likelihood that it is less than 100% is only 33.14% - ie, less than one chance in three. The IPCC final statement is more conservative than the graph, allowing a likelihood of not less than 95% ("extremely likely") that the anthropogenic factors caused more than 50% of the warming.
The IPCC can be this confident because the primary natural forcings (solar and volcanic) are known to have had a negative trend over that period; the ENSO influence is known to have been near neutral; and because the sixty year period provides a close coincidence with the period of natural cycles thought by some to have a significant influence on temperaure (AMO, PDO) and hence are neutral, or very nearly so. Other purported natural influences are either also negative because associated with one of the influences above (eg, cosmic rays), or of such poor scientific basis as to be magical thinking. Because of this, denying that the anthropogenic contribution over that period is in the range of (approximately) 75-125% amounts to magical thinking and/or pseudoscience.
What is worse, anthropogenic contribution is not constant over time. It amounted to less than 50% from 1901-1950, and likely around 30%, for example. Taking the 1901-2010 interval, it is closer to 75% than 100%. With ongoing emissions at a Business As Usual rate (RCP8.5), the anthropogenic contribution will become overwhelming. That is, it will still be close to 100%, but the probability of it falling below 75% will become vanishingly small unless something very unusual happens (ie, an increase in solar activity unprecedented in tens of thousands of years (and potentially over the entire life time of Sun to date). Further, because such natural factors are unpredictable, they are not included in the projection, so that if some unprecedented natural warming did occur, so that the anthropogenic contribution fell to 80%, then likely the total warming will have increased to 5 C, not the 4 C projected.
I am a teacher and one of my objectives is to
I need some help on what type of information to provide 7th graders to read and come to a conclusion on their own. I have printed some information from procon.org. Are there any other websites or information(7th grade reading ability) which I can share with them. I am staying away from indoctrination and trying to let them read and conclude through graphs and facts. Any advice?
Teacher:
The National Climate Data Center has an excellent web page. I used it in class (10th grade). I read the selection and then wrote questions on the things I thought most important for the students to read. The 2017 Global annual report is here. 7th graders could read the list of hot years and other graphs. Have students click on the Temperature Anomolies Time series annual at the very top to see the red graph (deniers complained so the graph was removed from the main report). Ask if the graph shows temperatures increasing or decreasing (no statistics needed).
The report for the USA only is here. I like to look at the seasonal graphs (at the bottom of the page) and ask the students if they see more red/orange or more blue (red is hot and blue is cold). A statistical analysis is not needed to determine there is much more red. You can just look at your state if you wish. The regional summaries are also good to read but may be hard for your students.
The National Snow and Ice Data Center has a good web page. The yearly summary is at the end of the January 2018 page here. Read the page first (it is too long for 7th graders) and then assign what you like (I really like the graphs). The October report here has good discussion of the minimum sea ice level and some interesting graphs. The sea ice maximum is generally in March but is not usually as interesting.
Good luck. Post again if those are too hard to read or not what you want.
Teacher:
As far as evidence of human influence, see the graph Sir Charles posted here. How can you look at the wheelchair graph, which clearly shows the natural influence for the past 5,000 years was cooling, and not see clear human influence? The natural change has been cooling for thousands of years, all heating is due to human influence.
The Skeptical Science Graphics page here has a lot of good graphs (no copy of the wheelchair). The obvious changes in many happening around 1880 demonstrate clear human influence.