date: Tue, 17 Jul 2007 15:26:15 +0100
from: Tim Osborn <t.osborn@uea.ac.uk>
subject: Re: carbon emissions
to: paul41@webone.com.au

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Dear Paul,

there is no absolute "proof" in science, but rather observations 
together with explanations for those observations that are called 
hypotheses, theories or laws (depending on the degree to which the 
explanation has been tested, how well it has passed those tests, and 
the degree to which it is generally accepted).

The greenhouse effect provides the link between extra carbon 
emissions and global warming, and is often described as a theory, 
given that it has been relatively well tested and as a result is 
generally accepted.

The greenhouse effect theory is complex, in that it depends upon many 
different processes each behaving according to various laws, e.g. the 
size of the increase in atmospheric CO2 concentration following extra 
carbon emissions is determined by various chemical and biological 
processes that remove some of the extra CO2, e.g. the effect of the 
remaining extra CO2 on the heat balance of the Earth is determined by 
various physical laws that quantify the emission and absorption of 
radiation by different gas molecules and that determine the flow of 
the atmosphere etc.

As a result, it is difficult to point you towards a single piece of 
research that is, on its own, able to demonstrate testing of the 
greenhouse effect theory, because acceptance is based on a huge 
number of studies that have tested individual processes or components 
within this complex theory, and even those studies that have 
attempted to test the overall sequence of events from carbon 
emissions through to global warming/climate change could not be 
relied upon individually -- rather it is the combined message from 
multiple studies that has led to widespread acceptance of the 
greenhouse effect theory.

The Intergovernmental Panel on Climate Change (IPCC) has reviewed and 
summarised many of these strands of evidence, so I would suggest that 
you read their recently-published summary for policymakers available here:

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_SPM-v2.pdf

especially, for example, the diagram on page 11.

This summary is based on a full report, the chapters of which are 
available here:

http://ipcc-wg1.ucar.edu/wg1/wg1-report.html

Chapters 1 and 9, together with the studies that they refer to, might 
be of most interest in terms of the development and subsequent 
testing of the greenhouse effect theory.

I hope you find this reply useful.

Best regards

Tim

>-----Original Message-----
>From: Margaret and Paul [mailto:paul41@webone.com.au]
>Sent: Monday, July 16, 2007 10:49 AM
>To: cru@uea.ac.uk
>Subject: carbon emissions
>
>Hi,
>
>I am an ordinary person, trying to fathom the whole global warming
>issue.
>
>I am trying to establish the proof that carbon emissions are causing
>global warming.
>
>Can you direct me to any research that proves this point.
>
>I am looking for proof, rather than an association.
>
>Many thanks,
>
>Paul Wright



Dr Timothy J Osborn, Academic Fellow
Climatic Research Unit
School of Environmental Sciences
University of East Anglia
Norwich  NR4 7TJ, UK

e-mail:   t.osborn@uea.ac.uk
phone:    +44 1603 592089
fax:      +44 1603 507784
web:      http://www.cru.uea.ac.uk/~timo/
sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm


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