An article by scientists Andrew Dessler and Steven Sherwood was published on Thursday in ‘Science’, and brings a new area for discussion regarding the issue of global warming to the forefront.
The article discusses the role that water vapour plays in the warming of the planet, and adds to the controversial disputes about whether global warming would have happened and be happening anyway, with or without human activity’s contribution.
Although it is true that the evaporation of water would occur anyway, the high amounts of CO2 released into the atmosphere every day by industrial processes and their effect on accelerating the speed at which the planet’s temperature is rising will inevitably cause more evaporation and therefore a higher level of water vapour in the Earth’s atmosphere. Therefore by continuing to release carbon emissions at our current rate, we are not only adding to levels of carbon dioxide in the atmosphere, but as result of a feedback reaction, means our actions are having twice the impact we may have first thought.
According to New Scientist, 50% of greenhouse gases are made up of water vapour, with CO2 being 20% by comparison. It may be easy considering this to think that if the water vapour is the bigger problem, why is everybody so worried about reducing CO2 levels in the first place, however the problem with carbon dioxide it that the level present builds up over a much longer period of time. The action we take now will not be seen immediately, but will be more a preparation for the future to try and prevent levels from spiraling out of control.
Of course there are also other contributors to the greenhouse effect, such as CFCs and methane, and their effects compared to the same amount of CO2 are much more destructive. The difference, however, is that the amount of CO2 is so much higher that the other gases are almost insignificant by comparison, so in light of this, the importance of continued campaigning to reduce the carbon emissions of the planet of a whole really is the best way forward to hopefully ensure a future for the human race.
More about the case for water vapour vs carbon dioxide can be found on the New Scientist website.