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二氧化碳不是决定气候变化的主要因素 (第2部分)

Al Gore: “Science is settled” Really? Is the earth temperature higher than 100 year ago? 1,000 years ago? or 1 million years ago?

 

Earth temperature is NOT as what most believed stable year over year. The earth has seasonal fluctuations. However, each year when the earth returns to the same positions relative to the sun, temperature is quite constant as it was. Astronomy studies told us that sun and earth are both at relative stable mid-age, and fusion reaction inside the sun will last another billions of years, keeping the earth warm and constant. 

 

Nevertheless, if we observe long-term trend of earth temperature, we can immediately find that surface temperate has a cycle of 100,000 years. This phenomenon was discovered by Serbian civil engineer and mathematician, Milutin Milankovic (1879-1958). In last 800,000 years, Earth temperate fluctuated with a distinct glacial and interglacial phase at an interval of about 100,000 years.  In each 100,000 years, earth temperature also fluctuated in shorter cycles, such as 40,000 year cycle, 21,000 cycle, 11 year solar cycle.  We can saw those cycles from tree rings and coral patterns.

Source: Rahmstorf and Schelinhuber, 2006

 

This 100,000 year long cycle was created by the earth’s orbit characteristics - precession (axial rotation), obliquity (axial tilt), eccentricity (orbit shape), and solar forcing. Those four factors run on different cycle and fluctuation. Once combining the effects of those 4 factors, they create earth’s temperature cycle that matches perfectly well with the glacial cycle.  This amazing model was called Milankovic cycle. 

 

 

 

 

Source: Milutin Milankovic

 

The most recent glacial age is consistent with the pattern of last 8 cycles.  Earth entered this warm, inter-glacial age about 18,000 years ago.  During previous 8 cycles, average inter-glacial time lasted about 15,000-20,000 years.  Hence, we are near the end of this warm, inter-glacial cycle.  Earth temperature is destined to be lower in the next 80,000 years. 

 

 

Source: Compiled by R.S. Bradley and J.A. Eddy based on J. Jouzel et al., Nature vol. 329. pp. 403-408, 1987 and published in Earth Quest, vol. 5, no. 1, 1991. Courtesy of Thomas Crowley.

 

Earth temperature has been rising in the last 18,000 years after the earth exited the most recent glacial age with the most rapid rise in the first 1000-2000 years. Sea level rose and life flourished since then.  The claim that earth is heating up by burning fossils has to be analyzed within a context.  Admittedly, CO2 is a greenhouse gas, but its impact on earth temperature is the difference between the actual rise minus background rise, and minus impacts from other factors.

There are numerous self-correcting mechanisms in regulating earth temperature.  Even burning fossil fuels can generate earth-cooling effects. Not long ago in 1970s, environmentalists, like Stephen Schneider, of the National Center for Atmospheric Research in Boulder, Colorado feared anthropogenic atmospheric pollution could block the sun and reduce earth temperature. Dusts from coal burning could form tiny aerosol particles that blocked the sun’s radiance, which offset the greenhouse effects of CO2. Also, many natural events can reduce earth temperature; for example, the volcano eruption at Pinatubo Mount in June 1991 reduced the global temperature by about 0.50C in following 2 years.

Between 1940 and 1970, the global average temperature did in fact appear to be cooling. (see the chart by Polyakov, 2004.) Then surprisingly - in the late 1970s the temperature stopped declining and surface temperatures during the 1980s and 1990s began reading small but steady increases from ground-based stations. Climate fears of "global cooling" suddenly changed to "global warming". 

What Determine the Surface Temperature of the Earth?

Average earth surface temperature is at 15OC, which is determined by the difference of incoming energy and outgoing energy. To understand the fluctuating earth surface temperature, we need to know what and how main factors affect the energy flow. How CO2, as a greenhouse gas, play a role in affecting surface temperature becomes clear after we analyze those factors. 

 

Source: NASA http://asd-www.larc.nasa.gov/erbe/components2.gif

 

Earth surface received radiation from the sun, at the upper atmosphere at an intensity of 1,367 watt/ per square meter. About 50% of that energy is absorbed by earth surface, 20% by troposphere and stratosphere and rest 30% are reflected by clouds. The surface then emits infrared radiation to release the energy, which was subsequently absorbed by greenhouse gases in the troposphere.

 

 

                 Perihelion       Aphelion         Mean

 

Direct Solar      1414 W/sqM      1323 W/sqM      1367.5 W/sqM

                                                  (433.6 Btu/ft2-hr)

 

Albedo            0.30+/-0.01     0.30+/-0.01      0.30+/-.01

(global annual

average)

 

Planetary IR     234 +/-7 W/sqM   234+/-7 W/sqM    234 +/7 W/sqM

(global annual                                     (72 to 76 Btu/ft2-hr)

average)

Source: Thermal Environments JPL D-8160.  http://www.tak2000.com/data/planets/earth.htm

 

The energy absorbed by troposphere was radiated back to earth surface, which cause a surprise fact that earth surface radiate more energy than it received from the sun.  Hence, troposphere is indeed a blanket covering the earth and most of that effect is from greenhouse gases. Without this blanket, earth temperature will be around -18OC and no life can survive.

 

Radiative forcing of greenhouse factors is the difference between incoming energy and outgoing energy, relative to the year 1750.  CO2’s radiative forcing of 1.66 means that CO2 kept outgoing radiation by 1.66 watt per square meter relative to the amount in 1750.  Radiative forcing is used to quantify the effects from various factors in trapping energy. 

Source: IPCC 2007

 

Based on Forster etc study, total radiative forcing relative to 1750 is 2.99 watt/m^2, with CO2 at 1.66, and CH4 at 0.48.  For CH4, its concentration has varied between 0.4 to 0.7 ppm by volume in last 800,000 year through glacial cycles. Its current concentration is 1.75 ppm, and remained constant in last 2 decades. Over a 100-year period, Methane is 21x times more potent in trapping heat in the atmosphere than CO2, according to the IPCC report.

 

Source: Climate Change 2007: The Physical Science Basis.   And EPA. 

 

CO2 accounts for more than half of greenhouse effects.  Since 1958, atmosphere CO2 has been continuously measured at Mauna Loa Observatory in Hawaii. Due to the planting season in north hemisphere, CO2 fluctuates by 5 ppm each year from Apr. to Oct.  In 50 years, average CO2 concentration has been rising steadily from 315 ppm in 1958 to 385 ppm in 2009.

 

 

 

 

Source: IPCC

Source: Scripps Institution of Oceanography

 

 

 

 

Longer term CO2 level in atmosphere was measured by ice core samples. In Antarctic, snow falls on snow each year. Some of those have not melted in last million years. Air sample from each year was trapped among ice particles.

 

Ice core drilled from East Antarctic ice sheet, scientists were able to back measure atmospheric concentration of CO2 back to past 800,000.  The time interval covered 8 glacial-interglacial cycles.  And resolution of the timeline was 1,000 years.

 

nature06949-f2

Source: Dieter Lüthi, etc. Nature 453, 379-382(15 May 2008)

 

Do CO2 Emissions cause Global Warming?

This is the most striking chart that has been used to illustrate the close relation between temperature and CO2. The rise and fall of the temperature almost perfectly CORRELATED with CO2 concentration.  Al Gore and the rest of the global warmists use this ice core data to convince the world that if we raise the CO2 concentration, earth temperature will follow.

 

This conclusion is seriously FLAWED!

 

This chart demonstrated only the close correlation between CO2 from ice core and calculated earth temperature. Because the resolution is 1000 years, we do not know which factor is leading the move.  Did CO2 rise follow temperature rise, or vice versa?

 

Close inspection of the data and other studies have suggested that the CO2 changes LAG temperature changes by centuries, although this lag was not clear in the Luthi’s graph due to the resolution of the data.

 

Hence, warming might be initiated by other reasons, and CO2 might be released from ocean water when temperature rose. During the 800,000 years, CO2 fluctuated between 170-300 ppm.  Current level as of 2008 was 382ppm, exceeding the highest level.  Apparently, the rising of CO2 during those cycles could not be attributed to human activities.  Dinosaurs did not burn any coal or crude oil. Mostly likely, the rising CO2 was the result of, not the cause of rising temperature. And earth temperature fluctuated in cycles according to Milankovic cycle. 

 

Rising CO2 could be the result of releasing dissolved CO2 in the ocean because of higher temperature in the atmosphere and the ocean. As water temperature rises, Co2 is released to the atmosphere, very much like opening a can of Coke. Ice core data did NOT prove that rising CO2, from anthropogenic activities, would cause rising temperature on earth. They only showed the historical synchronized movement between CO2 and temperature. 

 

Carbon reservoirs and cycle on earth surface are well summarized in this chart. 

 

Source: IPCC AR4 (2007) Fig 7.3. and by Joseph Priestley and Antoine Lavoisier; and L.R. Kump etc. The Earth System, 2nd edition

 

There are almost equal amounts of CO2 in the atmosphere and in the ocean surface water (760 billion tons and 1,050 billion tons respectively) and much more in the ocean as bicarbonate ions and sediment rocks. Carbon circulates among those forms in a short-term cycle, and a long term cycle. Long-term cycle refers to the movement between solid rock/fossil form and ocean/air form.  Over millions of years, carbon entering reservoir through formation of rocks and fossils exceeded carbon released from reservoir. Hence, the CO2 concentration in atmosphere today is much lower than it was 500 million years ago.  Through this long cycle, the balance among reservoirs determined CO2 concentration in the air. 

Description: Phanerozoic_Carbon_Dioxide

Source: GEOCARB, Berner and Kothavala, American Journal of Science 304: 397–437. 2001; COPSE, Bergmann et al. American Journal of Science 301: 182-204. 2004.

 

Short-term cycle refers to the movement of carbon among air, water, soil and biosphere, which usually takes months to years to reach equilibrium. In this short cycle, photosynthesis and physical dissolution moves carbon around. On average carbon molecules reside in atmosphere for about a decade.

 

Burning fossils fuel and cement production bring CO2 out of its huge, long-term reservoir to its transient reservoir, which is the air and ocean water. In 2007, 29 billion tons of CO2 were released into the air from burning fossil fuels. CO2 from burning fossil fuels, despite its huge tonnage numbers, was only a small fraction of CO2 emitted by plant decay.  Admittedly, plant decay emissions are balanced by plant growth each year, and burning fossils is a one-way street that is additive to CO2 in the air.

 

Can increased CO2 emission be offset somehow? Carbon storage and sequestration technology are still under development. Fortunately, nature already has its own negative feedback mechanism to offset elevated CO2.

 

First of all, plant growth will be better. Land plant growth in the nature is constrained by CO2. CO2 is food and nutrient for plants. Assuming other nutrients are given adequately, increased CO2 will enhance plant growth. We know that plants in greenhouse grow faster and bigger, under a CO2 concentration of ~1,000-1400 ppm.  Increased biomass growth will meaningfully reduce CO2 level in the atmosphere.

 

Second, ocean will absorb more CO2 if its level in the air is elevated. The balance of CO2 between air and water is governed by physical law - temperature and relative concentration.  As more CO2 accumulates in the air, more CO2 will be dissolved in the water. Increased CO2 in dissolved form will also help plankton and shell animal growth, which eventually deposit as carbonate on the ocean floor. 

 

This mechanism of CO2 absorption was researched and published in Science 305 (2004) by Chris Sabine etc. Of all human made CO2 emission since industrial age, 48% of them have been absorbed by the ocean.  Of course, this is NOT an excuse for us to continue burning fossil fuels.

 

Source: Marland etc. 2007.  US CDIAC.

 

Nevertheless, the impact of CO2 on global temperature is vastly exaggerated. All we know so far is that

 

CO2 concentration rose from 280 ppm to 380 ppm in last 100 years

Global temperature increased by 0.50C~ 0.70C at the same period (according to Hansen)

Highly synchronized movement of temperature and CO2 in last one million years.

 

But, we do not know which one is the cause, which one is the effect. Earth temperature rises and falls, depending on many factors. Many of these factors are beyond our control, such as solar spot activities and glacial cycles. The cycle of solar spot activity, which is beyond the scope of this article, is another important factor affecting the earth temperature. Additionally, sampling bias and statistical errors can totally distort results, despite available facts and data.

 

 

 

Misplaced emphasis on CO2 as the culprit of rising earth temperature


By now, it is clear that earth temperature is determined by a myriad of factors with solar radiation being the most important one.  Greenhouse gases are secondary factors that keep earth warm, but they are also subject to influence from human activities. Of the greenhouse gases, this is the order of importance:

 

1)    Water vapor

2)    CO2

3)    Methane

4)    NOx, SOx, and other

 

Why are we so obsessed with CO2? And point fingers to an obviously misplaced target? Should we focus on cloud formation? And methane?

 

A fortunate thing about the atmosphere is that there is a negative feedback system between clouds and temperature. If the earth temperature rises, more water vapor will accumulate in the air. More cloud will form if water vapor is increased. Clouds reflect solar radiation back to space and hence, reduce energy reaching earth surface. We are lucky to have white clouds and blue sky.

 

Additionally, one shocking fact about methane was pointed out by Steve Levitt in his best selling book Superfreakonomics. He said it was generally believed that CO2 generated from cars and airplanes heated up the earth. However, when we raise cow for beef, the cow’s dung will generate methane. Methane is 25x more potent as a greenhouse gas than CO2. The world ruminants are responsible for about 50% more greenhouse effects than the entire transportation sector!

 

Irreversible process? Try geo-engineering!

Al Gore: “We face the gravest threat that civilization has ever confronted. It's global in nature and requires a global solution. Increased CO2 emissions anywhere, whether from China or the United States or from one of the countries that is burning its forests like Brazil or Indonesia—from wherever the emissions come, they have the same effect: They trap much more heat from the sun, melt the ice, raise the sea level, cause stronger storms, floods, drought, bigger fires, generate millions of climate refugees, destabilize political systems, threaten the growing of food crops and cause a number of other catastrophic consequences which, taken together, threaten the basis for the future of human civilization on the Earth. Because these consequences are distributed globally, the problem masquerades as a distraction. Because the length of time between causes and consequences stretches out longer than we're used to dealing with, it gives us the illusion that we have the luxury of time. Neither of those things is true. The crisis is a concrete threatening reality today. It stands to get catastrophically worse unless we take action before the accumulation [of] this global warming pollution reaches such toxic levels that the problem becomes bigger than we can solve.

We're already at the point where it's stretching our capacity to reach an agreement that will solve the problem, but it's still within our capacity. There are abundant reasons for hope that we will act in time. If you look at the difference between today and 10 years ago, there is a global consensus. More than 70 leaders from nations are gathering at Copenhagen. Many nations have taken action and the world is waiting for the natural leader, the United States to move on this.”

In 2003 James Hansen published a paper called Can We Defuse the Global Warming Time Bomb where he argued, “human-caused forces on the climate are now greater than natural ones, and that this, over a long time period, can cause large climate changes.”  His view on actions to mitigate climate change is that "halting global warming requires urgent, unprecedented international cooperation, but the needed actions are feasible and have additional benefits for human health, agriculture and the environment.”

 

In a 2009 book, Hansen said, “Planet Earth, creation, the world in which civilization developed, the world with climate patterns that we know and stable shorelines, is in imminent peril. The urgency of the situation crystallized only in the last few years. We now have clear evidence of the crisis, provided by increasingly detailed information….” And that “the startling conclusion is that continued exploitation of all fossil fuels on Earth threatens not only the other millions of species on the planet but also the survival of humanity itself - and the timetable is shorter than we thought. “

 

It seemed doom and gloom after listening to James Hansen and Al Gore.  Even more depressing is that the COP15 in Copenhagen failed terribly and politicians from many countries were shortsighted as they cared only about re-election and GDP growth in their few years term.  People are burning coal and oil more feverishly than they ever did.  Are we heading to hell’s day on Earth?

 

In June 1991, Pinatubo Mount in Philippine, erupted intense sulfuric ash into the sky for 9 hours. It was the second most powerful eruption in the 20th century. Within 2 hours, sulfuric ash reached 22 miles high, discharged 22 million tons of sulfuric oxide to the stratosphere.

 

In following 2 years, heavy sulfuric ash acted a blanket for the region, and reduced world temperature by 0.50C! Isn’t that ironic? An unexpected Pinatubo volcano can reverse the entire rise of earth temperature caused by global industrialization. If the impact of sulfuric oxide was true, can we create an artificial volcano eruption to reverse the rise of global temperature?

 

Actually, a scientific solution can be much more elegant.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Geoengineering is a large-scale engineering of our environment, including soil, ocean, and atmosphere, in order to combat or counteract the effects of changes in earth’s climate system.

 

Source: nextnature.net and infowars.net

 

 

In 1956, a report called Restoring the Quality of Our Environment was drafted by US President’s Science Advisory Committee. It was the first high-level recommendation of a geo-engineering solution to modify earth’s heat balance.  “The possibility of deliberately bringing about countervailing climate changes…need to be thoroughly explored”

 

In 1991, a 917-paged book called POLICY IMPLICATIONS OF GREENHOUSE WARMING was published by a Committee on Science, Engineering, and Public Policy, National Academy of Sciences, National Academy of Engineering, Institute of Medicine The book presented methods for assessing options to reduce emissions of greenhouse gases into the atmosphere, to assist humans and unmanaged systems of plants and animals adjusting to the consequences of global warming, and to mitigate the effects of greenhouse gas emission.  “Undertake research and development projects to improve our understanding of both the potential of geoengineering options to offset global warming and their possible side effects. This is not a recommendation that geoengineering options be undertaken at this time, but rather that we learn more about their likely advantages and disadvantages.”

 

In 2002, Dr. Edward Teller, a Nobel Laureate responsible for the hydrogen bomb, submitted a article to National Academy of Engineering, with colleagues Roderick Hyde and Lowell Wood, suggested that geoengineering solution, not CO2 reduction, “is the path mandated by the pertinent provisions of the UN Framework Convention on Climate Change”

 

Failure of COP15 for countries to sign up for a CO2 reduction supported the need to develop a geoengineering solution. Emerging economies, particularly China and India, are heavily relying on coal to power their economies.  Brazil is fortunately powered by hydro and Russia by natural gas.  USA is also reluctant to cut emissions because 50% of its electricity is generated by coal. Despite repeated, tenacious efforts from global environmentalists and Al Gore, COP15 did not reach any tangible goals.  That should not surprise anyone because science is NOT settled.

 

Belarusian climate scientist named Mikhail Budyko first suggested spreading sulfur dioxide (SO2) in the stratosphere, to create sulfate particles that could replicate the effect of volcano eruption at Pinatubo Mount. Budyko's 1956 book, Heat Balance of the Earth's Surface, transformed climate research from a qualitative into a quantitative physical science. His new physical methods, based on earth heat balance, were quickly adopted by scientists in the world. By scientists’ estimate, 100,000-600,000 tons of SO2 per year will be sufficient to counter the warming trend. 

 

Additionally, Yuri Israel, the former Vice Chairman of IPCC, and Head of Institute of Global Climate and Ecology Studies at Moscow, sent a letter to President Vladimir Putin and suggested conducting a small-scale experiment of shooting SO2 to the air.

 

How to spread sulfur dioxide is a technical issue. There are many ways to conduct the experiment.  The critical message is that geo-engineering can save the earth. We are not doomed by burning coal.  Even if we burn all proven reserves of fossil fuels in one single day, the earth will be NOT destroyed – ocean will absorb half of the CO2, and plant growth will be better, although atmospheric CO2 may rise. Plant will yield 70% more mass if CO2 level is raised to 1200ppm (typical at commercial greenhouse) from 380ppm, assuming other conditions are equal. Temperature may be slightly higher, but it is reversible by spreading SO2.

 

Source: IPCC

 

IPCC estimated that in 2100, earth temperature might be 20C ~ 60C higher than today, depending on which model they use. While readers may be scared by the forecast rise of temperature by IPCC, scientists already have solutions.  In a report by The Swedish Society for Nature Conservation, they listed ten new ways to geoengineer the planet:

 

1)    Create vast monoculture tree plantations for biochar, biofuels & CO2 sequestration;

2)    Contaminate Centres of Genetic Diversity with DNA from genetically engineered crops;

3)    Fertilize the ocean with iron nanoparticles to increase phytoplankton that theoretically sequester CO2;

4)    Proliferate nuclear power plants

5)    Build 16 trillion space sunshades to deflect sunlight 1.5 million km from Earth

6)    Launch 5,000-30,000 ships with turbines to propel salt spray to whiten clouds to deflect sunlight

7)    Drop limestone into the ocean to change its acidity so that it can soak up extra CO2

8)    Store compressed CO2 in abandoned mines and active oil wells;

9)    Biannually, blast sulfate-based aerosols into the stratosphere to deflect sunlight;

10)Cover deserts with white plastic to reflect sunlight

 

 

STERN REVIEW AND HIS $1.2 TRILLION SOLUTION

 

On October 30th 2006, economist Nicholas Stern send a 700-page report to UK government, detailed climate change and its economic impact. It is the most comprehensive study and was widely discussed, both positively and negatively. Here are few excerpts of his conclusion:

 

“There is still time to avoid the worst impacts of climate change, if we take strong action now. The scientific evidence is now overwhelming: climate change is a serious global threat, and it demands an urgent global response. Climate change will affect the basic elements of life for people around the world – access to water, food production, health, and the environment. Hundreds of millions

of people could suffer hunger, water shortages and coastal flooding as the world warms.”

 

“Using the results from formal economic models, the Review estimates that if we don’t act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever. If a wider range of risks and impacts is taken into account, the estimates of damage could rise to 20% of GDP or more. In contrast, the costs of action – reducing greenhouse gas emissions to avoid the worst impacts of climate change – can be limited to around 1% of global GDP each year.”

 

He suggested the world to spend 1% GDP to develop new technologies, change economic structure, and reduce CO2 emission. In 2008, he raised his price tag to 2% of global GDP, or $1.2 trillion to fulfill the CO2 and temperature goal.

 

$1.2 trillion?!  Maybe $1.2 trillion will do the work.  Like many other problems, there are always solutions, but the issue is cost. If we stop all economic activities and return to Stone Age, we can surely stop emitting CO2.  Is that what we want?

 

What about a $250 million geo-engineering solution?

 

It is not time to implement geo-engineering solutions yet, but we should prepare a Plan B to save the earth in case all scares of global warming turn out to be true.  Given that impacts from geo-engineering may not be reversible and have a global consequence, we should be careful in designing and testing the solution, because we cannot conduct a large scale experiment without impacting the earth.

 

If the warming continues, which is unlikely and doubtful, sea level may rise to a disaster level so that hundreds millions people have to migrate inland from world’s coastal cities. Those solutions will be needed when New York, London, Hong Kong are under water and people have to swim for grocery shopping. Still, there is no urgency to implement the solution. For now, let’s test and develop those solutions, and keep the know-how in a closet.

 

Finally, in another millennium or so, earth will enter the next glacial phase that will definitely cool down the earth, and this global warming fever. 

 

 

 

因为我们不可能在地球表面的每一英寸上都安装一个温度计,所以对地球平均温度的估计是非常困难的一件事。地球温度只可能在地球表面有选择的地方进行测量和估计,那么这些测量点是均匀分布的吗?不是。那么,他们的这些气象站的位置有偏差吗?是的。大部分陆地上的气象站是建在50年代和60年代的,当时他们都处于主要城市的郊区,因为没有必要关心边远地区的温度和气候。那么,在过去几十年中,这些郊区发生了什么呢?他们现在都已经变成城市中心了,现在这些气象站围绕的都是高层建筑物,新建的火电站、购物中心和来来往往的车辆。

那么,这样的一个城市发展对所报告的全球温度有什么样的影响呢?这里是两个处于不同环境的气象站所报告的当地温度的变化趋势。在左边的一个气象站,周围的环境没有变化,所显示的温度在过去一百年中是稳中有降,而另外一个处于居民居住区的气象站则显示了当地的温度有一个升高的趋势。该气象站周围有空调的排气系统,电话的传播塔以及一个停车场。

迈克克里克博士是加拿大古夫大学的环境经济学教授。他是一个在加拿大和世界各地被经常引用的在全球变暖和环境政策问题上的专家,他接受过《时代周刊》、《纽约时报》、《华尔街日报》、《国家邮报》、《全球和邮件》、CBC、BBC、彭博通讯、全球电视等的采访,在这里显示的是一个全球平均温度和全球气象站数量的一个图表,图中显示自90年代以来,在俄罗斯、中国、非洲和南非气象站的数量有显著减少。这一气象站数量的减少,同时偶合全球平均温度的突然升高。那么现在提出的问题是,这些所减少的气象站是不是都在边远地区,而剩下的气象站都靠近城市中心呢?我们知道城市是有显著的热岛效应的,

资料来源:Dr. Ross Mckitrick.   http://www.uoguelph.ca/~rmckitri/research/nvst.html

资料来源: NASA map by Robert Simmon, based on data from the National Climatic Data Center.

大家显然都同意地球表面温度的测量很容易受各种偏差的影响。所以,根据陆地气象站所记录的温度进行平均,不是一个很可靠的方法,去回答地球是不是在变暖这样一个问题。抽样偏差和地球表面差异性很容易导致错误的结论。我们必须用不同的方法来测量地球的温度。那么,我们可不可以测量空气的温度和海水的温度呢?答案是确定的。从1958年,我们已经连续搜集了根据气球所载仪器的低层大气的温度(对流层大气 )。根据卫星所载仪器测量的温度,从1979年开始有连续的数据。这样的测量方式反映了真正的地球表面温度,根据IPCC所提议的气候模型,如果地球表面温度升高的话,大气的温度也应该随之升高,因为地球表面的辐射会加热大气中的空气分子。

根据气象气球和卫星上得到的数据,让全球变暖的信奉者失望了,这些数据没有显示地球表面温度像他们所期待的那样变暖的趋势。国家研究委员会在90年代评估了上空气层温度的趋势变化之后说道:

“自1979年以来,在低和中对流层,也就是从地球表面到5英里以上的大气范围内,有卫星和气球所载仪器采集到的数据显示了微不足道的温度变化。气候模型预测,如果温室气体是造成全球变暖的原因的话,上层的空气和地表温度都应该同时升高。”

一点都不奇怪,这样的在气象站和卫星数据之间的差别,在科学界引起了很大的争议。美国气候科学研究项目挑起了对于这些数据进行重新分析的重任,在几个不同的科研机构的共同努力下,他们仍然不能够达到一个决定性的共识。IPCC(那当然了)说这两者之间的差别已经不再存在,因为从卫星和气球上所得数据的误差已经被查明和纠正了,另外一些则说,调节数据和模型之间的差别仍然有很多问题。他们不认为卫星和气球的数据支持了地表气象站所显示的温度趋势。这里是摘自IPCC报告中卫星得到的温度数据,老实说,我看不到任何明显的趋势。

资料来源: IPCC - Climate Change 2001: Working Group I: The Scientific Basis Figure 2.12

如果我们观察地球温度的长期趋势,我们就会发现地球表面的温度有一个大概10万年左右的周期。这个现象是由塞尔维亚的工程师和数学家米兰科维奇发现的(1879—1958),在过去的80万年中,地球的温度在一个明显的冰川和非冰川期间波动,这个周期长度为10万年,每一个10万年,地球的温度又有一些短期的波动。比如说四万年的周期、两万一千年的周期和11年的太阳黑子周期,这些周期的变动,我们可以从树的年轮和珊瑚礁的生长周期中观察到。

这样的一个十万年的周期是由于地球轨道的三个特性,轨道的旋转、轨道倾斜、轨道的形状来决定的,加上太阳辐射的周期所共同影响了地球表面的温度,这四个不同因素有不同的周期和幅度,当把这四个因素加到一块的时候,他们所形成的周期和过去八十万年的冰川周期完全吻合,这样一个近乎完美的模型就叫做米兰科维奇周期。

资料来源: Milutin Milankovic

我们最近经历的一个冰川时代和过去的八个周期是一致的,地球开始变暖,离开上一个冰川期,大概是一万八千年左右。在前面的八个周期中,这样两个冰川期之间的时间间隔大概是一万五千年到两万年,所以我们目前所处的这个温暖的冰川间时代已经是接近尾声了,地球的温度在未来的八万年肯定是逐渐降低的。

(资料来源:R.S. Bradley and J.A. Eddy 《自然杂志》329卷403页到408页,1987年。 《地球探索》第五卷第一期,1991年)

地球温度上升最快的时期是在离开上一个冰川时期的最初的一千年到两千年,在随后的一千八百年,温度是逐渐上升的。在这个期间海平面上升了一百多米,地球上的生命也随之欣欣向荣。所以说地球是由于燃烧化石而变暖,一定要放在一个大的自然环境下去分析。二氧化碳作为一个温室气体对地球温度的影响,不单单是地球实际温度的升高,因为这里面包括了其他自然因素的影响。有很多自我调节的机理在控制地球的温度,甚至燃烧化石也会产生一些让地球变暖的因素。环境学家施奈德,科罗拉洲的国家大气研究中心在70年代所担心的是人类活动产生的污染会遮住太阳的辐射,因此而导致地球温度降低,燃烧煤炭所产生的尘埃,在空气中形成小的微粒,可以阻止太阳的辐射。这样的一个效果可以抵消二氧化碳的温室效应,同时还有许多自然现象也会降低地球的温度,例如1991年6月菲律宾的。皮纳图博山的火山爆发,导致了地球在接下来的两年中温度降低了0.5度。

在1940年到1970年,地球的温度看上去确实是在降低。(见2004年保利科夫的数据)在70年代之后,温度突然停止下降,在80年代和90年代温度开始有一个很小但是稳定的上升,这些数据是由地面气象站的数据提供的。从那以后,媒体和公众所担心的地球变冷,突然就变成了担心全球变暖。

哪些因素决定地球表面的温度呢?

地球表面的温度是15度,是由进入地球和离开地球的能量之差所决定的,为了理解地球表面温度的波动,我们需要理解由哪些因素影响地球的能量流动,又是如何影响地球温度的。这样二氧化碳在影响地球表面温度的角色,在分析了这些因素之后就很清楚了。

资料来源: NASA http://asd-www.larc.nasa.gov/erbe/components2.gif

地球表面的能量来源于太阳的辐射,在大气的上空,这样一个辐射强度为每平方米1367瓦,太阳的辐射30%被云层所反射到宇宙中,另外的20%左右被对流层所吸收。到达并被地面吸收的大概是50%,地球表面在吸收了这些能量后,又以红外线的方式把能量释放回去。这些红外线在释放的过程中,又被温室气体所吸收。

Perihelion       Aphelion         Mean

Direct Solar      1414 W/sqM      1323 W/sqM      1367.5 W/sqM

(433.6 Btu/ft2-hr)

Albedo            0.30+/-0.01     0.30+/-0.01      0.30+/-.01

(global annual

average)

Planetary IR     234 +/-7 W/sqM   234+/-7 W/sqM    234 +/7 W/sqM

(global annual                                     (72 to 76 Btu/ft2-hr)

average)

资料来源: Thermal Environments JPL D-8160.  http://www.tak2000.com/data/planets/earth.htm

对流层的温室气体吸收的能量,一部分又返回到地球表面,所以,造成了一个很奇怪的现象是地球表面所释放的能量比它从太阳中接收的能量要多。所以大气中的对流层就像一个毯子一样,包裹着地球。这样的一个“毯子效应”  主要是由于温室气体造成的,如果没有这样的一个毯子,地球的温度将会降低到零下18度左右,地球上的生命将不复存在。

温室气体的辐射强度是用相对于1750年输入能量和输出能量之差来衡量的。 二氧化碳的辐射强度因素1.66,意思就是二氧化碳的1.66辐射强度意味着,相对于1750年的数量,二氧化碳保留了向外辐射1.66瓦/平方米的能量。辐射强度是用来量化各种因素保留能量的效果。

资料来源: IPCC 2007

根据费斯特等的研究,辐射强度的总值相对于1750年是2.99瓦/平方米,二氧化碳的效果是1.66瓦/平方米,甲烷是0.48瓦/平方米。甲烷的浓度在过去80万年中,波动的幅度为0.4到0.7ppm,它目前的浓度是1.75ppm,在过去的二十年中保持得很稳定。把二氧化碳和甲烷做比较,在一百年的时间范围内,甲烷保留能量是二氧化碳的21倍。这一计算是根据IPCC的报告。

资料来源: Climate Change 2007: The Physical Science Basis.   And EPA. 

二氧化碳的效果是占所有温室效应的一半,自从1958年大气中的二氧化碳的观察数据是由夏威夷的莫纳·诺亚观察站提供的,由于北半球植物生长的周期性,二氧化碳每年从4月份到10月份的波动幅度大概是5ppm。在过去的50年中,平均的二氧化碳浓度由1958年的318ppm升高到2009年385ppm。

资料来源: IPCC

资料来源: Scripps Institution of Oceanography

更早和更长周期的二氧化碳浓度是用冰芯样品来测量的。在南极洲,每年一层冰压在另外一层冰上,南极的很多冰已经保存了好几百万年。每一年的空气样品就保留在这些微小的冰块之间。根据南极洲的冰芯样品,科学家可以推算一百万年以来大气中的二氧化碳浓度,这样的时间间隔可以覆盖过去的八个冰川、非冰川周期。这样的一个时间表的分辨率为一千年。

nature06949-f2

(数据来源:罗西等《自然杂志》453卷,379-382,2008年5月15号)

二氧化碳导致全球变暖吗?

上面这张图被用来证明地球温度和二氧化碳的高度相关性,地球表面温度的起落和二氧化碳浓度的变化几乎是完美的相关。戈尔副总统和其余的全球变暖倡导者用这个冰芯数据向全世界证明,如果我们继续升高二氧化碳浓度的话,地球的温度也会随之升高。

但他们的这个结论是有严重缺陷的。

这张表所显示的只是冰芯中的二氧化碳浓度和计算出来的地球温度的高度相关性,因为这个时间表的分辨率是一千年,我们并不知道哪个因素是原因,哪个因素是结果?是二氧化碳导致温度升高了,还是温度升高导致二氧化碳变化?我们对这些数据的仔细分析,综合其他研究证明,二氧化碳的变化落后于温度变化几百年,但这样的一个落后在罗西等的图表中是看不出来。所以,变暖有可能是由于其他原因造成的,而二氧化碳是由于从海水中被释放出来,当温度升高的时候。在过去的80万年中,二氧化碳的浓度波动在170到300ppm。目前2008年的温度为382个ppm,超过了历史的高位。很显然,过去的二氧化碳浓度的变化不可能是由于人为的原因造成的,恐龙并没有去烧煤或者石油。所以,最有可能的解释是二氧化碳的升高是温度变化的结果,而不是原因。地球温度的变化是由米兰科维奇周期来调节的。

当海水温度升高的时候,溶解在海水里的二氧化碳就会被释放到大气中,就像我们打开一瓶可口可乐一样,所以,冰芯的数据并不证明人造的二氧化碳会导致地球温度升高。他们显示的只是历史上二氧化碳和温度的同步运动。而我们更相信,这个看上去同步的运动,实际是温度的变化领先于二氧化碳浓度的变化。

资料来源: IPCC AR4 (2007) Fig 7.3. and by Joseph Priestley and Antoine Lavoisier; and L.R. Kump etc. The Earth System, 2nd edition

碳的储备池和碳循环由上表进行了概述,大气中和海水里所含有的二氧化碳大概差不多(大气中为7600亿吨,海水中含量为10500亿吨)。更多的碳是以碳酸盐形式和沉积在海底中的岩石,碳循环有短周期和长周期,长周期指的是在固态的岩石和化石的形式和海洋空气中所存在的气态的形式之间的运动。在过去的几亿年中,进入岩石和化石储备池中的碳超过了从储备池中释放出来的碳。所以,今天大气中的二氧化碳比五亿年前要低得多。通过这样的长周期,不同储备池中的平衡,决定了今天大气中的二氧化碳。

Description: Phanerozoic_Carbon_Dioxide

(资料来源:博纳和克斯瓦纳《美国科学杂志》2001年304卷397页到437页,和伯格曼等《美国科学杂志》301卷182页到204页 2004年)

短周期指的是碳元素在空气、水、土壤和生物圈之间的运动,这样的运动一般需要几个月到几年达到平衡。在这样的一个短周期中,光合作用和物理溶解是碳运动的动力。平均来说,碳分子在空气中的平均周期为十年左右。

燃烧化石和制造水泥等,把二氧化碳从它的长期储备池中带到短暂的储备池中,也就是空气和水中。2007年燃烧化石燃料总共释放了290亿吨的二氧化碳,虽然这样的吨位数很巨大,但它只是植物降解所产生的二氧化碳的很小的一部分(5%左右)。确实植物降解的过程是被每年植物生长所平衡的。而燃烧化石是一个单向的运动,

那么空气中增加的二氧化碳的排放量,有没有什么机制可以抵消呢?二氧化碳的储藏和固定技术仍然需要完善,但幸运的是大自然已经提供了一个负反馈系统去调解升高的二氧化碳水平。

第一,植物生长会更加强盛,陆地上的植物生长在自然中是受到二氧化碳的局限的,二氧化碳是植物的食物和能量。假设别的营养条件是相同的,增加的二氧化碳可以增强植物生长,我们知道温室中的植物生长得更快更大,其中的二氧化碳浓度大概是1000到1400个ppm左右。增加的植物生长可以有效降低大气中二氧化碳水平。

第二,如果空气中的二氧化碳浓度升高的话,海洋会吸收更多的二氧化碳。空气和水之间的二氧化碳平衡是由物理学性质所决定的,也就是温度和相对浓度。当空气中积累的二氧化碳的更多的时候,更多的二氧化碳就会被溶解在水中。当空气中的二氧化碳浓度升高的时候,水中溶解的二氧化碳也会随之升高。水中增加的二氧化碳会帮助浮游生物和贝壳类动物的生长。因为他们需要碳元素作为生命的组成。这些生命最终会以碳酸盐的形式沉积在海底。这样的一个二氧化碳的调节机制是由克瑞斯·赛冰等研究并发表在《科学杂志》305卷2004年上。

自从工业革命以来,人类所排放的二氧化碳48%已经被海洋吸收了。但这并不给我们使用化石燃料提供更多的借口。

资料来源: Marland etc. 2007.  US CDIAC.

然而二氧化碳对地球温度的影响被夸大其词了,我们目前所知道的只是:

  1. 在过去的一百年中,二氧化碳浓度从280ppm增加到380ppm。
  2. 全球温度(根据汉森等)在同时期内增加到0.5到0.7摄氏度。
  3. 在过去的一百万年中,二氧化碳和地球温度的运动是高度同步的,

但是,我们并不知道在温度和二氧化碳之间谁是原因,谁是结果。地球温度的升高和降低是由很多因素决定的,许多这些因素,例如太阳黑子活动和冰川周期都是我们无法控制的。尤其是太阳黑子是影响地球温度的一个重要因素。还有一点即使我们有了数据和事实,抽样偏差和统计错误能够完全改变研究结果和得到的结论。

把二氧化碳作为造成地球温度升高的主要原因是错误的,讲到这里已经很清楚了,地球的温度是由很多因素决定的,尤其是太阳辐射,温室气体是次要的因素,他们帮助地球保暖,同时也会受到人类活动的影响。在温室气体中,它们的重要性是这样排列的,

  1. 水蒸气。
  2. 二氧化碳。
  3. 甲烷。
  4. 氧化氮、氧化硫等。

为什么我们都指责二氧化碳是气候变暖的主要原因呢?我们是不是应该研究云层和甲烷的影响呢?

幸运的是,大气中的云层和温度也是一个自我调节的负反馈系统,当温度升高的时候,更多的水蒸气就会聚集在空气中,这样就会形成更多云层,而云层可以把太阳的辐射返回到外层空间,所以可以减少地球表面所接收的热量。所以,我们很幸运有白色的云层和蓝蓝的天空。

另外一个让人很震惊而难以置信的事实是最近由史蒂芬·列维特在他的畅销书《超级魔鬼经济学》中指出来的。他说大部分人都认为开汽车和坐飞机产生的二氧化碳导致了全球变暖,而我们都没有意识到牛粪中产生的甲烷对大气的影响。我们并没有想到减少我们对牛肉的消耗,因为甲烷作为一个温室气体,它的效应是二氧化碳的25倍,所以今天地球上的反刍动物像牛类所产生的温室效应比整个人类交通运输所产生的温度效应要多出50%。

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