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標題: 氣候異常
alex07055
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發表於 2012-11-23 20:22  資料 短消息 
氣候異常

我不是專家,只是分享一下個人感受

近來氣候異常怪異...
氣溫,濕度時高時低,現在11月中,可以時一天17-18度,第2天25度up
以這星期來說,氣溫,濕度讓我以為是春天,香港以往何時有過這怪異的天氣
冬天起霧,以天文台資料,近2星期時間保持多雲有雨,濕度70以上的冬天
讓我不禁聯想起世界沒日論,其實就算是真的,也是人類做成的吧

唉,這種天氣,讓我的郊遊行山行澗連改了多次時間...大失預算呢
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siuyuen
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發表於 2012-11-23 23:53  資料 短消息 
到底是正常定係異常.....不同的科學家有不同的見解,有說是溫室現象加劇,又說只是氣候循環...不需驚訝....

真係世界怪得誇張..
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alex07055
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發表於 2012-11-24 14:00  資料 短消息 
回覆 #2 siuyuen 的帖子

不同見解皆有之
但可見,人類對地球做成的污染已影響了整個地球生態,氣候的運作

嘿嘿,今日無落雨,可以去camp了@_@
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pyling (快樂的小魚兒)
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發表於 2012-11-28 01:44  資料 短消息 
回覆 #2 siuyuen 的帖子

"不同的科學家有不同的見解,有說是溫室現象加劇,又說只是氣候循環"--> Majority of earth scientists acknowledge that climate change has already been happening and is out of the ordinary climate cycle.

The others are mostly working for the oil companies, or opportunistic that they could be famous some day in case they are right (because they are the minority, they would be famous if climate change is proven not happening).

Because of fair treatment of reporting, news media (in the US, they are mostly controlled by oil companies or their friends) will broadcast "both sides" of the story to "balance out". But if you review the credited peer-review journal articles, 99.9% of them agree that climate change that is currently happening is already out of the ordinary.
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jasonpoon
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發表於 2012-12-8 13:26  資料 短消息 
We may not know the climate changes in very details beyond the Quarternary, so it is still arguable whether the climate changes in last 100 years represent actual human activities influence after industrailization and city developments OR some natural longterm fluctuations occuring before modern human appeared.

Look at the glacial periods, such large fluctuations of temperature were very much bigger in scale than what we are now seeing. And such changes - glacial and inter-glacial periods - occurred very frequently in geological time over the past million-years. We are still figuring out how rapid could be the transition from glacial to inter-glacial periods. There were drastic temperature, sea-level, polar ice, glacier activities changes, not to mention the micro-climatic and weather extremes.

So looking on a larger scale, some scientist and myself would put certain doubt on, say, "total" human contribution towards recent climate changes, though I totally accept the fact that the earth has been warming up for the past 100 years.
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發表於 2012-12-9 02:09  資料 短消息 
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"it is still arguable whether the climate changes in last 100 years represent actual human activities influence after industrailization and city developments OR some natural longterm fluctuations occuring before modern human appeared"--> we will only know this definitely 500-1000 years from now. This is basically much of the consensus in the scientific community.

Ok, you do admit that human beings' do contribute to the recent climate change, with some unknown percentage.
1. Everyone agrees here that the recent climate change is making our livelihood worse but not better.
2. Food insecurity is getting worse.
3. Habitat of a lot of species are disappearing due to climate change and/or habitat destruction.
4. Habitat destruction contributes to climate change. (if anyone doesn't know why, please look it up).

Look at the reasoning as follow:
1. Shortwave energy coming from the sun is relatively constant.
2. Increase concentration of Greenhouse gases in the atmosphere absorbs some of the longwave energy emits from Earth back to the space.
3. Energy balance has to hold true.
4. Currently incoming shortwave energy>outgoing longwave energy.
5. According to 2nd Law of Thermodynamics, the increase in temperature of the Earth can lead to increase amount of outgoing longwave energy.
6. In order for incoming shortwave energy=outgoing longwave energy to happen, Earth temperature is going to increase until it reaches equilibrium.

Please tell me if there's anything wrong with my above reasoning.

Nevertheless, regardless of the percentage the human beings is contributing to the current unwelcome climate change phenomenon, we should stop habitat destruction AND decrease emission of Greenhouse Gases. Even if we cannot stop the trend (if according to your hypothesis that it is part of a longterm natural phenomena), we should not exacerbate it.
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發表於 2012-12-9 02:11  資料 短消息 
回覆 #5 jasonpoon 的帖子

"There were drastic temperature, sea-level, polar ice, glacier activities changes"--> Please educate me when in the Earth's history can we see such a high RATE of climate change (so fast in such a short time)?
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發表於 2012-12-9 09:46  資料 短消息 


QUOTE:
原帖由 pyling 於 2012-12-9 02:09 AM 發表
"it is still arguable whether the climate changes in last 100 years represent actual human activities influence after industrailization and city developments OR some natural longterm fluctuations ...

I only reply on the "causes" or "explanation" of the observed fact of global average warming as discussed. No doubt I agree that no matter the earth is warming or cooling and by whatever reasons, human activities have already done too much in too fast a rate to change many habitats on a global scale and that much stronger awareness and actions on conservation are needed long long ago.

We must separate theoretical explanation with practical conservation action. The latter should be done much earlier before full theoretical understanding, same as the case of biology vs medicine.

Global drastic or rapid changes, of whatever factors, will worsen any status quo, whereas any slow changes will be better adapted.

Interestingly, some changes attributed to global warming is of questionable detrimental effects, e.g. the more northerly and southerly extension of coral reefs, extension of certain fisheries like from the Atlantic to the North Sea. Even the recent appearance of anadromic gobies in some other places like Hong Kong as I suspected.

The earth's food supply problem, I think, is very complicated but it is more related to uncontrolled population,  political, commercial, distribution and other human evils.

Habitat destruction contributes to climate change but the vice versa may not be in the same rate. Relatively rapid habitat destruction caused a chain of events adding to slow global temperature rise that in turn change physical and biological factors that in turn change or worsen the change in habitats.

As for your "reasoning", may I first clarify your points:
1. Average solar heat is relatively constant. Heat that cause rise in temperature should be carried mainly by long wavelength part of sunlight, i.e. infrared rather than the short wavelength ultraviolet, is that what you mean by "shortwave" and " longwave"?  If yes your "shortwave" should not concern heat transfer as UV is not involved in solar heat transfer. The difference in temperature with and without sunlight, as maybe exemplified by the temperature difference in day and night time of deserts, or more drastically the front and back sides of the moon. So it is the sun's input of "longwave" and the earth's loss of "longwave" to outer space that is concerned with your "balance" right?
2. Greenhouse gases, basically carbon dioxide, is said to REFLECT rather than absorb heat. Its proposed that part of the heat that should have been lost to outer space was reflected back to the earth by carbon dioxide in the atmosphere causing temperature rise.
3. Yes, the Law of Conservation of Energy is assumed.
4. I would say over the last 100 years we see incoming solar heat > outgoing heat loss to outer space.
5. Yes, so in theory the global warming effect of carbon dioxide is lessen by the increase rate of heat loss due to increased temperature. However, I do not know how significant is this effect.
6. The balance sheet is simple on large average global scale. However, many smaller scale effects that affect our livelihoods need to incorporate many other factors, I may think of the solar cycle, solar wind and spots activities, earth's recent change in magnetic field or possible nearing the time of magnetic reverse, volcanic or seismic activities, oceanic current and the "conveyor belt" system, not to mention the many anthropogenic factors.

[ 本帖最後由 jasonpoon 於 2012-12-9 14:26 編輯 ]

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pyling   2012-12-10 02:58  種子  +10   感謝分享 Thanks for sharing !
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發表於 2012-12-9 18:36  資料 短消息 


QUOTE:
原帖由 pyling 於 2012-12-9 02:11 AM 發表
"There were drastic temperature, sea-level, polar ice, glacier activities changes"--> Please educate me when in the Earth's history can we see such a high RATE of climate change (so fast  ...

By the words "glacial" and "inter-glacial", the difference is graphic enough. As for the "rate" of the change is currently everyone's guess. I do not have any capacity to teach you or anyone, what I have always been doing here are sharing or presenting views that I know, heard of or believing myself. I am open and prone to mistakes and I just hope to learn something from ones mistakes and to share the views and info by the wide and fast audiences here.

Some evidence suggesting a relatively rapid rate are the extinction and replacement of many huge land mammals - the so called "megatheria" with similar but much smaller ones presumably since the last glacial periods. One interesting case being the discovery of many seemingly freshly frozen mammoths at northern Eurasia. It maybe hypothesized that a relatively rapid global or micro climatic change may have caused the phenomenon. One would also speculate that times near the "turning points" of climate, whether from cold to warm or from hot to cool, will be accompanied by micro climatic or weather extremes similar to those we are encountering these days.

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pyling   2012-12-10 03:03  種子  +10   感謝分享 Thanks for sharing !
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發表於 2012-12-10 02:57  資料 短消息 
回覆 #8 jasonpoon 的帖子

"We must separate theoretical explanation with practical conservation action. The latter should be done much earlier before full theoretical understanding, same as the case of biology vs medicine. "--> Absolutely agree!

1. No, shortwave energy includes gamma ray, X-ray, etc. The spectrum of the incoming energy from the sun is much wider that ultraviolet-infrared.
2. No and no. Greenhouses gases also include methane, NOx, etc. They BOTH absorb and reflect.
6. The solar cycle, solar wind and spots activities are taken care of if you look at it from a point of the energy received by the Earth. Ocean current is driven by the heat distribution in the ocean, aka, the heat that we receive.


To better illustrate my point about energy budget, please read the following. If you have no time, then please look at figure 1 at least.
http://www.cgd.ucar.edu/cas/Tren ... AMSmarTrenberth.pdf


Thank you very much! It is very nice to have such discussion with you!
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發表於 2012-12-10 03:03  資料 短消息 
回覆 #9 jasonpoon 的帖子

"One would also speculate that times near the "turning points" of climate, whether from cold to warm or from hot to cool, will be accompanied by micro climatic or weather extremes similar to those we are encountering these days."--> Yes. In order to understand whether we are a the "tipping point" or we are at transition to the "Alternative stable state" is something we can only know after at least 500-1000 years.

By the way, I highly recommend the short article in my previous message.
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發表於 2012-12-10 20:51  資料 短消息 
1. No, shortwave energy includes gamma ray, X-ray, etc. The spectrum of the incoming energy from the sun is much wider that ultraviolet-infrared.

Of coz the whole EM Spectrum is involved in solar radiation BUT we are talking about heat and temperature here, so only the "longwave" - to be more precise infrared is involved. Remember heat is carried by infrared, whereas shorter wavelength radiations like untraviolet, X-Ray, Gamma Ray etc are having different effects on the environment. Your ref article also clearly indicated "OLR - Outgoing Longwave Radiation" and seems not mentioning "shortwave". So quoting your own: "4. Currently incoming shortwave energy>outgoing longwave energy." seems mistaken at least incoming energy (that affects temperature) is concerned.

2. No and no. Greenhouses gases also include methane, NOx, etc. They BOTH absorb and reflect.

I was saying basically carbon dioxide. I do not see any contribution from "absorption" in the figure of the article either. I may not be update but the more evidenced fact was that as far as warming is concerned, the reflection back by carbon dioxide is the predominating and perhaps the only significant factor as far as Greenhouse Gases were concerned. Whereas in case any Greenhouse Gases would "absorb" heat, this would in reverse contribute to "cooling" the earth! Remember, only "free energy" in the atmosphere / land / ocean will "heat up" the earth!

3. The solar cycle, solar wind and spots activities are taken care of if you look at it from a point of the energy received by the Earth. Ocean current is driven by the heat distribution in the ocean, aka, the heat that we receive.

Basically agree, I just want to point out that the 11-year or so Solar Cycle is of much concern in view of recent weakening and possible point of magnetic reversal. This would cause thinkable major disarster if the earth's magnetic field is even temporarily rip off... The Oceanic Current or Conveyor Belt System is mega and ancient and just imagine that it would take thousands or more magnitude of years for some water bodies that went down to resurface. The effects of any disturbance to this ye-olde system need much investigation and theorizing.

[ 本帖最後由 jasonpoon 於 2012-12-10 20:54 編輯 ]
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發表於 2012-12-10 21:17  資料 短消息 
回覆 #12 jasonpoon 的帖子

1. Energy incoming must equal to outgoing energy.
2. Currently due to absorption of outgoing longwave energy by greenhouse gases, the Earth increase its temperature according to the following equation: S[pi*r*e^2] = (sigma*T^4)(4*pi*r*e^2).
3. Sorry for forgetting to include slides about absorption of energy by greenhouse gases.

Please read the following lecture slides for simple and better illustration of what I am talking about and GHGs aborption of energy:
http://shadow.eas.gatech.edu/~jean/paleo/Lectures/Lecture_2.pdf
http://www.ess.uci.edu/~yu/class ... temperature.all.pdf
http://www.elmhurst.edu/~chm/vchembook/globalwarmA5.html
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發表於 2012-12-10 21:19  資料 短消息 
回覆 #12 jasonpoon 的帖子

" I do not see any contribution from "absorption" in the figure of the article either."-->It's in the text. But all those 3 links of lecture slides are figures.
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發表於 2012-12-10 23:27  資料 短消息 
I think recently there have been some incorporation of the absorption effect as indicated.

But in any consideration, the relatively much lower global average concentration and production of GHGs other than carbon dioxide, the effect must be viewed as secondary or minor. Remember the global conference just closed last week, they are still sticking to arguments around the Kyoto Protocol, which is carbon dioxide emission.

Solving the carbon dioxide concentration issue will resolve the warming effect by, I speculate, over 95%.

[ 本帖最後由 jasonpoon 於 2012-12-10 23:37 編輯 ]
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發表於 2012-12-11 21:06  資料 短消息 
回覆 #15 jasonpoon 的帖子

Yes, carbon dioxide, although not the most powerful, but the most abundant. Methane is 25 times more powerful and it comes from cow farms, paddy fields, and mangroves, etc. We basically cannot control water vapour. That's why carbon dioxide is always on the news.

Ai, but the US, Japan, Australia, etc are still not participating in it.
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發表於 2012-12-16 10:36  資料 短消息 
今年真係好怪,明明十二月應該日日成個天都係altocumulus, altostratus, stratus, stratocumulus, 但而家日日都係cumulus
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發表於 2012-12-16 16:20  資料 短消息 
回覆 #8 jasonpoon 的帖子

人類發展對大自然所做成的影響已看得到
大面積熱帶雨林消失,
海,淡水受污染
人類通訊科技的能量波,頻率對生物的影響
廢氣,greenhouse gas ,城市熱島校應,屏風作用..
等等無數人為因數已影響到地球的正常運作
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發表於 2012-12-17 00:36  資料 短消息 
回覆 #18 alex07055 的帖子

agree, global warming is but one of the major issues of anthropogenic environmental degradation.
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