Naked Science Forum
Life Sciences => The Environment => Topic started by: yor_on on 29/03/2013 16:27:11
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Well, it made me smile at least - A little pearl of climatic wisdom -
How to respond to people who say the cold weather disproves global warming? (http://grist.org/news/how-to-respond-to-people-who-say-the-cold-weather-disproves-global-warming/)
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Unfortunately, the writer doesn't understand the first scientific point he tries to make (which only attempts to explain the general coldness of winters), and he still gets it wrong after two supposed updates. I quote the link and emphasize the point —
1. It is winter. More specifically, it is January.
The person to whom you are speaking may have noticed over the course of his life that it always gets colder during the winter, at least for those of us unlucky enough to live far from the Equator. Average temperatures in New York City for January range in the low 30s. Right now it is colder than that, but warmer than the all-time low for the date: 2 degrees, set in 1976.
This happens, you should remind the person, because the Earth doesn’t rotate straight up and down. The Earth’s axis is tilted. So for part of the year as the Earth rotates around the Sun, the Southern Hemisphere is farther from the Sun than the Northern Hemisphere. When that happens, the Southern Hemisphere has shorter days and less sunshine, affecting the average temperature. Now, the opposite is true.
Now give them a little pat on the head by suggesting that if it were this cold in, say, July, they’d be right to find it suspicious. But thinking it’s weird that it’s very (but not exceptionally) cold in January is like being puzzled when water they put in the freezer turns to ice. Then ask them if they know how to make ice in a freezer. If they say no, just drop the whole thing.
Mentioning the distance from the Sun suggests that the inverse square effect is the only/greatest cause of the coldness of winters, when actually, the multiple causes are due to the mechanics of a sphere rotating on a tilted axis. I don't know why the writer started off talking about summertime, which causes the author to say "Now, the opposite is true", where "now" doesn't mean "in our times of global warming" (as some might suppose), but instead means "in the wintertime" (shown below).
The tilt during winter in the northern latitudes causes —
- The northern latitudes to receive fewer hours of sunshine,
- The northern latitudes to receive less sunshine due to the tilt of the Earth's surface there,
- The sunshine dissipates through more atmosphere because of the Sun's lower angle to the horizon in northern latitudes, and
- The inverse square effect (but it is the least effect).
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.nature.nps.gov%2Fviews%2Fkcs%2FMilankovitch%2FImages%2Ftilt_22.gif&hash=8e25e50d17c0b1ea15dd4a6e72bbf86b)
source (http://www.nature.nps.gov/views/kcs/Milankovitch/Milankovitch.htm#)
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Is there any way to predict the effects of increasing amounts of C02 in the earth's atmosphere without using any of the data on past warming or cooling trends on Earth, or are there simply too many variables or unknown variables?
Sometimes global warming skeptics remind me of a someone saying, " I know smoking can cause cancer, but has it actually given me cancer yet? My cough and difficulty breathing could just be allergies or bronchitis, not cancer." In which case, they may be right, but is that a reason to keep smoking?
In other words, is dumping large amounts of C02 likely to be a good or even negligible thing? Or is there simply no way to know that without relying on actual warming trend data in the last 400 years or so? How good are computer simulations at predicting large, long term earth events?
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Prediction of anything relies on having a quantifiable theory, hopefully with a good scientific basis, and then to apply the the theory to the data available. The long term nature of climate change means that a lot of historical data is needed. This data should be used both to verify that the theory would have correctly predicted previous climate events and to add greater precision to any future prediction. There are a lot of variables but that is no reason to assume that it is impossible to make valid judgements regarding those which are important and those which can be neglected as being insignificant.
The problem with climate change issues are that there are huge financial and political motivations for acceptance or denial of the scientific consensus that (deliberately) confuse public opinion. If you want to examine how much a state's national interests, particularly short term interests, are able to sway public opinion, this issue is a prime example. By and large, major oil/gas producing nations do not believe there is global warming or, if they do now they have taken a fall back view that it is not man-made and nothing can be done. It is surprising how much the media, and, maybe as a result, the populace fall in with this view; it maybe that this is because most of the media, where not overtly politically biased, are controlled by people whose backgrounds are rarely in science and take an even view (as they see it) between scientific opinion and some politically motivated opposition.
I think that the climate models are the best that can be done with the data available. There is plenty of motivation to try to achieve better. The general discussions between climate scientists is not whether there is man-made global warming but how fast and to what extent it will affect the earth and what will be the long term consequences. There are other discussions about what should be done where it may be argued that it is too late to affect the situation and effort should be made to start to adapt (also a fall back for former "deniers" but where there maybe some agreement on a way forward).
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True Graham :)
It's funny how all those officials succeed in sounding so pompously 'right' at all times. Especially considering how fast they change opinions? They exhibit a great trust in mankind miserable long time memory, don't they?
And Lm**, it wasn't the scientifically perfect procedure that made me smile, it was the humor :)
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To follow up on what Graham pointed out, there is a lot of work to be done on models: for example, The Economist this week has an article on how global mean temperature has remained fairly constant for the past decade or so: http://www.economist.com/news/science-and-technology/21574461-climate-may-be-heating-up-less-response-greenhouse-gas-emissions
As they correctly point out, this isn't a case against climate change, but a sign that we probably don't have the best possible models yet since the earth's climate is incredibly complex. Climate change denialists who don't understand the scientific method will say that this small set of data proves that greenhouse gasses are harmless. Scientists, meanwhile will compare the overwhelming data for greenhouse gas induced climate change to this small set of anomalous data and seek to refine their models to best explain all the data.
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True Graham :)
It's funny how all those officials succeed in sounding so pompously 'right' at all times. Especially considering how fast they change opinions?
Quote from John Stuart Mill: "The more things change, the more they remain the same."
There are basically only two different reasons people change their minds;
They are honest enough to accept another truth when it surfaces.
or.................
They are attempting to just stay relative whether they have learned anything or not.
Sadly, many people fit the second category.