Talk:Climate change/Archive 3
Is there any consensus that the last ice age ended because of greenhouse gases? If not, then saying global warming is caused by greenhouse gases implies that the warming that ended the last ice age was a different phenomenon. It would be strange to say that the warming of the earth that ended the last ice age was not an instance of global warming.
This may be relevent since some people may claim that any global warming we are experiencing today is part of the broad historical trend that began thousands of years ago and is not a new, man-made development. So distinguishing between the naturally occuring climate change and any human-induced climate change may be desirable. - TS
I have a complaint about this article, in that I believe that it makes a very common mistake of mixing basic and uncontroversial scientific information with a decidedly normative view of the consequences of change. The article treats global warming as a bad thing, which it may well be, but it does so without a balanced presentation of the potential benefits. I think there's a natural and common tendency to assume that any change to the climate is bad, but this needs to be demonstrated, not assumed.
It is thought that the reduction in forested area has also played a factor, as forests convert these gasses back into organic materials.
- reduction of forested area can cause global warming because large amounts of CO2 are produced by fire or degradation of organic materials. But, ancient forests like Amazonia in Brasil were in steady state before man arrived there. That is, the amount of CO2 produced was equal to the amount consumed. Growing forests like the ones in North America and Russia are consuming large quantities of CO2. And the destrution of equatorial forests is producing CO2. I think there is no mention in the IPCC reports to the destruction of forests as a cause of global warming, but I can be wrong.
- some of the consequences in the article are not proven or are not major consequences or probable ones. For example, we do not know if polar caps are melting or will melt in the next one hundred years.
I think it's rather odd that the first paragraph seems to imply that global warming is a permanent, important problem, and then further down there is this: "There is no final consensus about existence of global warming. Temperature is changing all the time and there were hotter times in last thousand years, so it's unsure whether "global warming" is long-term issue or just a short-term fluctuation." If we're going to say the latter, we should say it earlier on. I'd work on this more myself but basically I don't want to get involved in a flame fest. :-) --LMS
I'm not real happy with this (and some related) articles either and they're on my to do list, but they've been slipping a bit lately. --Pinkunicorn
I've moved the bits on the IPCC to later in the article since I think a discussion of what the phenomenon is believed to be should come before a discussion of who is studying it. --KQ
- I added the bits about the IPCC because think we need to present what the phenomenon is as oposed to what phenomenon is believed to be and the IPCC is the only good source of information. This is a very controversial issue and I think we must present the facts, not the perceptions of the general public. joao
I would recommend restructuring the article so that it lists in order a) what it is, b) what is the evidence, c) what are the suspected causes, d) what are the suspected effects. Right now, these points are all scattered through the article in a confused and disorderly manner. - Tim
That sounds like a good suggestion, Tim. Joao, don't shout, please. :-) I recognize that there is controversy about it; I just moved the info because I thought it made more sense to explain the topic before introducing whoever's studying it--for someone who doesn't know what the topic is, that approach is both distracting and uninformative. Tim's suggested approach seems the most logical. We should not forget to add dissenting opinions at the end, since the subject is controversial. --KQ
Sorry, I maybe wrong on my comment above. However, we must take into account that there several points of view. The point of view of:
- the general public
- a minority that believes there is no global warming
- the (IPCC) scientists that collect facts and who believe gobal warming is hapening
- other scientists that point to flaws in the IPCC work
- economists who believe that does not pay to avoid global warming
- people with a political agenda who use global warming to change society and to get into power.
- people who believe that we must weigh both the costs and the benefits of climate change
- people who believe that such a chaotic and uncertain systems such as long-term global weather patterns cannot be predicted with sufficient accuracy to justify a particular course of action.
I' m going to add more information from the IPCC report. Since english is not my native language I will have some dificulties integrating it in the structure suggested by Tim, so be free to edit everything I write.
Sure, that sounds fine. And actually you've listed some points of view I hadn't considered; we should probably add those also. --KQ
I just added a paragraph about the causes of climate change. Some of them can cause climate warming and some of them can cause climate warming. Its because the ones that cause climate warming are more important that climate change is happening. joao
Some scientists believe that there are benefits to agriculture in the Northern Hemisphere precisely because of longer growing season and higher CO2 concentrations. joao
Article on that here: http://www.scientificamerican.com/news/090501/1.html --KQ
I deleted the following since I think it is now included in the text:
There is no final consensus about existence of global warming.
Temperature is changing all the time and there were hotter times in last thousand years,
so it's unsure whether "global warming" is long-term issue or just a short-term fluctuation.
I moved some other parts of old text.
I changed the struture proposed by Tim above:
a) what it is
b) what is the evidence
c) what are the suspected causes
d) what are the suspected effects
and I added:
e) prediction of future trends
Now I think we need to add:
f) possible future effects
g) proposed solutions
h) economic analysis
i) political debate
Information to add later to the article if needed
The IPCC analyzed the consequences of observed warming on the snow cover an ice extent, global average sea level , precipitation, cloud cover, El nino and extreme Whether events.
IPCC reports that:
- satellite data show a decrease of 10% of snow cover since late 1960s
- There has been a widespread retreat of mountain glaciers in non-polar regions during the 20th century
- Northern Hemisphere spring and summer sea-ice extent has decreased by about 10% to 15% since the 1950s.
- it is likely that there has been about 40% decline in Artic sea-ice thickness during late summer to early summer to early autumm in recent decades and a considerably slower decline in winter sea-ice thickness.
- tide gauge data show that global average sea level rose between 01. and 0.2 metres during 20th century
- precipitation has increased over high latitudes of Northern Hemisphere and tropical land areas and decreased between 10 N and 30 N during the 20th century
- heavy precipitation events increased by 2% to 4% in the high latitudes of Northern Hemisphere over the latter half of the 20 th century
- cloud cover increased by 2% over mid to high latitude land areas of Northern Hemisphere
- Warm episods of El Nino have been more frequent, persistent and intense since the mid 1970s compared with the previous 100 years.
deleted this information because I think it's not true that the oceans are releasing CO2. Oceans are absorbing CO2. However, this information can be added later under the correct context.
Many people believe that increased of concentrations of greenhouse gases (mostly CO2) in the atmosphere, which causes more of the energy radiated from the Sun to be absorbed by the Earth might be one of causes. But it could also be a result, as solubility of CO2 in water is smaller in high temperatures, so oceans are releasing more CO2 to the atmosphere as the temperature raises.
Oceans are not just water. It's a fact that in higher temperatures, solubity of almost all gases is smaller,
and it becomes smaller quite fast. The only important exception is the hydrogen.
But there is life in oceans that might have opposite reaction to temperature and level of CO2 in atmosphere,
therefore reaction of ocean waters != reaction of oceans.
And this version isn't NeutralPointOfView. --Taw
This is really shaping up well, Joao - and it's readable, too! --MichaelTinkler
Regarding the link to the Skeptical Environmentalist. I think that it would be in our best interests, considering NPOV, to have links to more information on both sides of the debate, but that is not what this is. This link does not go to an exposition, a paper, or even a summary of a book, but to a page whose main intent is selling the book. Isn't this really more of an advertisement than actual information? --Josh Grosse
I agree. Find or write a summary instead, or remove the link. --Pinkunicorn
- The Kyoto Protocol can also be evaluated by comparing costs and gains. Several economical analyses were made that show that the Kyoto Protocol is more expensive than the global warming that it avoids.
what's the IPCC point of view on this?
I removed the italicized quote above from the main page, to keep the discussion here. --Pinkunicorn
However, the number of scientists expressing skepticism on the
global warming issue continues to grow (see [Heidelberg Appeal]?, [Leipzig Declaration]?).
This is not NPOV. Who says the number of scientists expressing skepticism on the global warming issue continues to grow? They desagree about what? That there is no Global Warming? That Global Warming is not important? It's not antropogenic? Joao
However, data from weather satellites and balloon instuments show no warming whatsoever, which calls into question how well
land station data has been corrected for the urban heat island effect.
Is this true? Joao
- I agree with your comments, and have removed both texts in question. The first of those statements that you question is simply not true, and for the second one, see this web page:
http://www.cnn.com/2001/TECH/science/03/14/greenhouse.gases.02/
Concerning this sentence:
"Scientists are divided on whether this is actually so, although some political groups insist that "the science is settled.""
My understanding is that the vast majority of scientists accept that global warming is in fact occuring and a problem.
Wouldn't it be more accurate, and NPOV, to change this sentence to,
"Most scientists agree that global warming is occuring, although some political groups insist that "the science is unclear""
?
SR
- It would be accurate, if you cited a poll of scientists, especially those studying the atmosphere. The phrase "science is settled" is, I believe, a political statement -- not a scientific one. If you find the source to be otherwise, I will stand corrected.
- If you just read what the popular media report on this controversy, you get almost exclusively one side. The http://www.sepp.org site shows that the science is not settled and that substantial groups of scientists publicly disagree with the UN's report. Ed Poor
I disagree with recent changes to this articles. The article was previously written based on two main scientific sources: the IPCC reports and Lomborg's book. They represent good scientific sources and were used to represent the scientific debate. The view of the IPCC was used to represent the view "of the majority of the scientists" and Lomborg to represent "the critics". Both represented the last stage of the scientific debate. The article now changed: opinions, and not facts, are presented at the top of the article. I believe that controversial political issues should be moved to the end. This article was about Global Warming, now is about Anthropogenic Global Warming. I also disagree with this change. There are no "Global Warming advocates", because "Global Warming" is an observed trend, not a political cause. Global Warming is a fact. Anthropogenic Global Warming is under discussion and the majority of scientists favor the Anthropogenic Global Warming hypotheses. The previous version was NPOV by stating facts, this version is NPOV by attributing opinions, as if facts could be a matter of opinion. You can't say " Global Warming, advocates say, is a world-wide climatic phenomenon--the average global surface temperature increased over the last 150 years." because that is a fact, not just an opinion, in accordance with the evidence presented in the next paragraph. IPCC's Data was corrected for the urban island effect, so I don't see how someone can claim Global Warming doesn't exist.
- I as well think that version 81 was better. Version 81 started with Global warming is a world-wide climatic phenomenon--the average global surface temperature increased over the last 150 years. Whether this increase is significant or not is subject to debate.
- Now it begins with According to the global warming theory,... which sound strange. Temperatures have been measured for a considerable time and elementary statistics to do trends is known for a long time as well. So a global warming in recent times can be considered a fact. The questions is if it is significant or not.
- I vote for reverting to version 81. --HJH
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Someone deleted 1,008 words of talk from this page. Was that accidental? I'd like to think so. Ed Poor