Letter: Fletcher doesn’t get science of global warming

…in the last interglacial warm period…temperatures were 2.5 to 3 degrees warmer than today, while sea levels were five to 10 meters higher…

To the editor:

Re: Tom Fletcher’s column, Warming Industry Cries Wolf, Again, Kelowna Capital News, Friday, May 6.

It appears as if much of the bluster in this column is based on some misconceptions or errors in the understanding of the science behind our current climate changes or global warming.

To try to minimize the potential impact of a 1.5 degree warming over the past century or so by stating that this is “only one hundredth of a degree per year,” ignores the impact that this rate of change, which is predicted to continue at least at this rate, will have.

Consider that in the last interglacial warm period some 110,000 years ago, global temperatures were 2.5 to 3 degrees warmer than today, while at the same time sea levels were five to 10 meters higher than today.  No wonder then, that the scientific community strongly wants to limit global warming to no more than two degrees and preferably to less than 1.5 degrees.

As far as to whether CO2 changes lag temperature changes, this is certainly true when the Earth comes out of or into an ice age every 110,000 years or so.  During this time temperatures rise as a consequence of changes in the Earth’s orbit around the sun causing the Earth to be closer to the sun and hence receiving more heat from it.

A delayed increase in CO2 follows as it is released from warming oceans, much as it is released as fizz from a warming soft drink bottle. A reasonable equilibrium is then reached where temperature and CO2 concentrations are stable—a situation that has existed since the end of the last ice age about 10,000 years ago.

That is until man started burning fossil fuels beginning in the later part of the 19th century.  From this point onward, CO2 concentrations have increased from 280 parts per million to 400 parts per million today.  Through the greenhouse effect, temperatures then increase, but lag the increase in CO2.

Similarly, when the Earth’s orbit moves further from the sun, temperatures drop, we slowly enter another ice age and the oceans, with a delay, again take up CO2.

What this clearly illustrates is that today’s temperature changes have a different cause from those that cause ice ages to come and go.

As far as the contribution of water vapour is concerned, it is certainly an effective greenhouse gas, which is taken into account in any modelling, but it has not changed to the extent that CO2 has and as such cannot be a cause of changes in temperature.

Although the above is a brief description of the science behind our changing climate, what is clear is that man-made CO2 is the culprit and that unless we stop spewing it into the atmosphere the consequences are likely catastrophic—imagine Vancouver with sea levels five to 10 meters above where they are today, and never mind the more frequent and severe storms and droughts that are occurring worldwide.

Jan Conradi, Kelowna