If the evidence for global warming is so overwhelming?
But one thing I do not understand is that according to this chart
http://www.globalwarmingart.com/wiki/ima... sulphate levels were falling during this time. Should they not have been rising after 1940 and then falling after 1975?
And why did temperatures start to rise during the early part of 20th century when we had high levels of sulphates (which should have produced a cooling), and low levels of co2?
Answer:
Global warming was around long before humans were around. Scientific evidence has shown that our world goes in cycles. NASA reports have shown that we are in a trend in which our Earth is getting a tiny bit closer to the sun, which appears to be a normal cyclical event.
I agree that we ourselves are not helping with all of the chemicals we put into the atmosphere, however, we had an ice age, it melted, we had another ice age, it melted, and then we had yet another ice age and it too is melting. Had humans been around during those previous ones, they too would be blaming themselves.
It is both natural and man made-- consider this- of course there is sulfate in the air- sufate comes from volcanoes, and alot is escaping from Yellowstone (a super-volcanoe) as I type this. It is a natural event, but I feel that we should strive to clean our environment up because we want to ensure a clean place for our future generations, who will adapt to the climate changes, just as man has for thousands upon thousands of years.
By the way, temperatures started to rise during the arly part of the 20th century, for the same reason they did back in 10,000 BCE. It is a naturally occurring event.
Global warming is just that. Our efforts to change the trend, if it truly exists, will match that of the Y2K panic of Jan. 1, 2000. There will be more money spent to accomplish less than for any other hoax in history
You do not consider Al Gores movie, the science community's "consensus" and a bunch of old hippy's web sites to be hard evidence.
You have committed blasphemy in the church of liberalism.
There are a great many confirming studies.
Here's a bibliography of about 75 papers on it:
http://www.greenhouse.crc.org.au/crc/res...
Some of the best are listed as references in this document:
http://ipcc-wg1.ucar.edu/wg1/wg1-report.
Google "global dimming" for more information and references on this.
Here's roughly what the Meehl paper (the source of the chart) says in words.
In the early 1900s a combination of increased solar radiation, greenhouse gases, and low volcanic activity caused warming. About 1940 increased sulphate emissions became enough to stop that trend. About 1960 the increase in greenhouse gases became large enough to overcome the sulphate. Since then, greenhouse gases have been driving the train.
A key factor is that nothing can explain the warming in the past 25 years except greenhouse gases. Leave them out and you cannot match the observed data, the numbers just don't work.
Some more info and several abbreviated refernces here:
http://www.realclimate.org/index.php/arc...
that site is down right now, try
http://64.233.167.104/search?q=cache:hhw...
I'm not an expert you are probably right about sulphates
being higher but saying global warming is a theory is like smoking causes cancer is also a theory.
Face it cars burn gasoline a toxic chemical you and I burn about 9-15 gallons of it a week that is about 10000 gallons every week for 1000 people even though your car filters most of the emissions their are millions of drivers in each state.
Stand in a room with ten people who smoke no open windows open the window the close it again if you see the stupid point pollution has more toxic output than the earth can handle it is warming up the atmosphere Its a fact anyone who thinks different is in serious denial.
You're not reading the graph correctly. The graph is not the amount of greenhouse gases or sulphates or ozone or volcanic/solarness, it's the amount they impact the global temperature. Sulphate is increasingly negative in the plot because it has a cooling effect and its concentration is increasing. Thus it's causing more and more cooling. As you can see, its downward (increasingly negative) trend started around 1940.
In the early 20th century you can see that increased solar activity and increased greenhouse gas concentrations are overwhelming the fairly constant sulphate concentrations, causing global warming.
The problem with your argument here, is it implies that global warming theory assumes CO2 to be the only driver of global climate. Which is blatantly false. There are scads of different things that could warm and cool the atmosphere, such as increases in solar activity, human emissions of greenhouse gases, increase of decreases in volcanic activity, variations in Earth's orbit, etc. For example, it is believed that the warming prior to the 1940's was primarily due to changes in solar activity.
The fact that the CO2 signal was temporarily overwhelmed during the mid twentieth century is by no means evidence that it lacks the capacity to drive climate.
You are reading the chart incorrectly.
The chart does not show "levels" of sulphate. The chart shows the radiative forcing as a result of various causes. This allows you to compare the effect of, say, CO2 against solar against volcanic against sulphates on a single scale.
The sulphate levels are negative, indicating that the effect of sulfates is cooling. The more negative the sulphates get, the more the cooling effect. Thus the chart supports the sulphate hypothesis very nicely: sulfates continue to rise, and continue to cool the planet, but have been overwhelmed by the warming of CO2.
Here are the references you asked for:
Haywood, J.M., and O. Boucher, 2000: Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: A review. Rev. Geophys., 38, 513–543.
Vestreng, V., M. Adams, and J. Goodwin, 2004: Inventory Review 2004: Emission Data Reported to CLRTAP and the NEC Directive. EMEP/EEA Joint Review Report, Norwegian Meteorological Institute, Norway, 120 pp.
Streets, D.G., et al., 2003: An inventory of gaseous and primary aerosol emissions in Asia in the year 2000. J. Geophys. Res., 108(D21), 8809, doi:10.1029/2002JD003093.
Lefohn, A.S., J.D. Husar, and R.B. Husar, 1999: Estimating historical anthropogenic global sulfur emission patterns for the period 1850-1990. Atmos. Environ., 33, 3435–3444.
Van Aardenne, J.A., et al., 2001: A 1 x 1 degree resolution dataset of historical anthropogenic trace gas emissions for the period 1890-1990. Global Biogeochem. Cycles, 15, 909–928.
Boucher, O., and M. Pham, 2002: History of sulfate aerosol radiative forcings. Geophys. Res. Lett., 29(9), 22–25.
Stern, D.I., 2005: Global sulfur emissions from 1850 to 2000. Chemosphere, 58, 163–175.
Smith, S.J., E. Conception, R. Andres, and J. Lurz, 2004: Historical Sulphur Dioxide Emissions 1850-2000: Methods and Results. Research Report No. PNNL-14537, Joint Global Change Research Institute, College Park, MD, 16 pp.
Pham, M., O. Boucher, and D. Hauglustaine, 2005: Changes in atmospheric sulfur burdens and concentrations and resulting radiative forcings under IPCC SRES emission scenarios for 1990-2100. J. Geophys. Res., 110, D06112, doi:10.1029/2004JD005125.
Dentener, F., et al., 2006: Emissions of primary aerosol and precursor gases in the years 2000 and 1750 - prescribed data-sets for AeroCom. Atmos. Chem. Phys. Discuss., 6, 2703–2763.
Penner, J.E., et al., 2001: Aerosols, their direct and indirect effects. In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T., et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 289–348.
Tang, I.N., K.H. Fung, D.G. Imre, and H.R. Munkelwitz, 1995: Phase transformation and metastability of hygroscopic microparticles. Aerosol Sci. Tech., 23, 443.
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