If all your observations led you to theorise that your
house was, in twenty years time, going to fall off a cliff, would
you stay for 19 years just trying to prove you were
wrong?
Nothing irritates a scientist or an aspiring scientist more than
being told something is a certainty, a fact. The scientific
language is one of ideas and observations that are developed into
hypothesis and theories through intensive tests and retests not
just by the originator but by many other scientists.
According to Stephen Hawking in
A Brief History of Time, "a theory is a good
theory if it satisfies two requirements: It must accurately
describe a large class of observations on the basis of a model that
contains only a few arbitrary elements, and it must make definite
predictions about the results of future observations".
Man-made climate change
The theory of anthropogenic climate
change, that is man-made climate change, fulfills these
two tests. Recorded observations of temperature, humidity and
air pressure and of ice cores,
fossils,
tree rings,
sea floor sediments,
lake bed sediments, have been fed into
computer models that make predictions about
future climates. Hypothesis supporting the role of
carbon dioxide, methane, and other gases
that influence the climate have been tested and retested and
the increase of them through human activities has been
observed.
Now Stephen Hawking goes on in his book to irritate the
non-scientist by saying "any physical theory is always provisional,
in the sense that it is only a hypothesis; you can never prove it.”
We want certainty - fact. Yet the annoying reality is that as more
evidence is found and understanding develops through
experimentation theories will change. Scientists and non-scientists
will rightly continue to challenge the theory of man-made climate
change. Natural contributors to past climate changes -
solar activity,
meteorite strikes, changes in ice cover,
movement of land, and other contributors have been or are still
being explored but none have the balance of evidence in their
favour.
At the moment the theory that man's release of greenhouse gases
is responsible for the present changes in our climatic system is
the strongest theory. In that light, large organisations,
governments across the globe and individuals recognise that action
to reduce greenhouse gas emissions is a sensible and urgently
needed precaution when coupled with adaptation. This action
requires combined effort, leadership, investment and
change.
Further information
A basic explanation of climate science -
non-governmental, non-peer reviewed, privately funded international
climate change website.
The Intergovernmental Panel on Climate Change -
largely funded by governments from UN countries this body involves
approximately 600 specialists as well as government officials. They
review current scientific research findings related to climate
change and produce detailed and overview guidance to help
governments develop appropriate policy.
RealClimate
- commentary on climate science news by climate scientists, with
discussion.