I met a chatty cabby the other day, and found myself getting annoyed as he explained how he thinks climate change is a hoax. I see from a recent Monbiot article that there is a mini heatwave of scepticism due to the recent temperature data showing 2008 was a cool year.
I’d always thought that people who don’t believe in climate change are just ignoring the overwhelming evidence because its uncomfortable for them, and reminded them that in 1987 the UN General Assembly adopted a report which said that climate change is happening and we are causing it and its a problem, so that the real issue is why we live in a world where we have to wait for 20 years until a movie moves the public debate forward.
I decided to check up on the latest sceptics arguments and the counter arguments, as Id got the cabby’s email and was going to write to him. In doing the search, I realised that climate change proponents are partly at fault for the ongoing scepticism, for continuing to present a graph of temperature and CO2 correlation as if proving human induced climate change, rather saying it shows there are positive feedbacks on Co2 levels when temperatures increase (which when you prove with other data that CO2 increases temperatures, this positive feedback becomes more worrying).
So, now to the substantive section of the email I wrote to my driver….
“I found the following are the main arguments used against climate change:
1) “the Earth ain’t warming”
- evidence for this is last 10 years when global ambient temps have been steady while co2 has increased 4% in this time
2) “if it is its because of natural processes not us”
- evidence for this are the graphs mapping CO2 and temp rise over 1000s of years that show temperature rise happens before the CO2.
3) “if it is because of us then its more because of them, not me/us, and it doesn’t matter anyway.”
- evidence for this is that somewhere else is industrialising so fast so it doesn’t matter what we do (the West speaking of the Rest), or somewhere else has already benefited and we should catch up (the Rest speaking of the West), or that the cost of action is too expensive (as people look at costs of switching away from carbon intensive economies).
The evidence I have read to counter act these claims are the following. It seems most of these issues are dealt with in the IPCC reports (perhaps all, I haven’t time to go through all sources at http://www.ipcc.ch).
2) To: “the Earth ain’t warming”, with the evidence for this is last 10 years when global ambient temperatures have been steady while co2 has increased 4% in this time
- the Earth has warmed in the decades previously as carbon has increased.
- the melting of the poles has increased in the last 10 years significantly in ways that are affecting ocean currents, and sea temperatures, leading to a decline in the heat transportation effect of currents like the gulf stream, which has lost about 30% of its power. Thus, there has been cooling in certain places, such as Europe, while there is still warming in other areas, creating an overall appearance of temperature stability in the last 10 years.
- Modelling predicted volatility in temperatures as a result of more energy in the atmosphere. i.e. more energy retained in the atmosphere due to being trapped by greenhouse gases (most of those with carbon in them, like methane, co2, CFCs etc), does not necessarily mean more immediate heat, as melting ice absorbs energy. Yet this does mean more volatility, and we are seeing greater intensities of droughts, floods and storms, as predicted by more energy in the atmosphere overall. Once the ice cover is reduced, then the energy will produce greater heat rise.
- Atmospheric particulate pollution is causing a shielding affect, reducing sunlight hitting the ground, leading to slightly lower temperatures than if this effect were not occurring. naturally this happens when volcanoes erupt. However, its happening because of our dirty forms of industrialisation and transport, worldwide. This process has been called Global Dimming. The problems with particulate pollution are huge, and so efforts are under way to reduce them, and thus the dimming effect will be reduced.
2) To: “if it is its because of natural processes not us”, with evidence for this being the graphs mapping CO2 and temp rise over 1000s of years that show temp rise happens before the CO2.
- the geological record shows what happened before humans affected atmospheric chemistry. Before we did that, climate change occurred probably due to changes in solar radiation and events like meteorite strikes. Changes generally occurred over thousands or 10s of thousands of years. Thus when the temperature rose, this would dry out peat bogs, cause droughts and thus more fires, and all this would increase the CO2 in the atmosphere. It is true, therefore, that these graphs do not prove that CO2 and other greenhouse gases drive temperature changes in the past. Their use in presentations to argue for climate change is therefore unwise. However, the proof that CO2 and other greenhouse gases capture heat in our atmosphere is beyond doubt, as its basic science that can be conducted in any school laboratory – the molecules in these gases trap more infra red. No greenhouse effect, no life on earth, as it would be too cold. Therefore it is the most basic logic that tells us more greenhouse gases equals more energy trapped in the atmosphere. Some scientists were even predicting this, on the basis of this simple logic, about 100 years ago.
- what the graphs show us is that there is a major feedback loop, for when temperatures rise, for whatever reason, this makes the ecosystem release more carbon dioxide into the atmosphere, consequently maintaining and possible escalating the heating effect. This is what worries many climate scientists.
- a rise in greenhouse gases damages the oceans through acidification. so even if it doesn’t impact on climate (which is does), we should be concerned about what more acidic oceans will mean for marine life, and the social and economic implications
3) To “if it is because of us then its more because of them, not me/us, and it doesn’t matter anyway,” with evidence for this being that somewhere else is industrialising so fast so it doesn’t matter what we do (the West speaking of the Rest), or somewhere else has already benefited and we should catch up (the Rest speaking of the West), or that the cost of action is too expensive (as people look at costs of switching away from carbon intensive economies).
- If the West doesn’t act then it will be more difficult to persuade the rest of the world.
- If the rest of the world just blames the West then they will miss out on more energy efficient forms of economic development
- if we don’t act now the costs will be far greater in future (cf the Stern and Garnaut reports)
- if we don’t act now then we will have to face peak oil in any case, and so we need to transition from a hydrocarbon society in any case.”
I’m a bit hurried this weekend as leaving the country on Monday, so haven’t popped in all the references, but wikipedia is a good layman’s jumping off point for more evidence on these issues.
There is one lesson I learned from checking back with the science… that the image that might make the best communication tool may not actually be the right one to use. The hockey graph, showing CO2 and temperature levels over hundreds of years does not on its own effectively predict a temperature rise because of C02. More concerning, it shows a likely CO2 rise due to our heating of the planet. Other evidence shows that human released greenhouse gases are creating that initial temperature rise, and an increased level of energy in the atmosphere, resulting in increased weather volatility. Many climate change proponents use that graph without nuancing what it means, because that would get to complicated: which means they shouldn’t use it.