As the world faces more and more extreme weather events, and New Zealand suffers from severe droughts, the links between these events and climate change and not being reported correctly by the media. Florence Issacs gives us the lowdown and joins the dots.
Climate change calls to mind a great deal of things – authoritative figures yelling about carbon credits, graphs with red spikes, solemnly-nodding scientists and likely an association with extreme weather; or at least a barrage of Day-After-Tomorrow-esque images.
Perhaps your thoughts are currently with those in the regions of the North Island, facing very desperate times in what has come to be recognised as the worst drought in 70 years. Perhaps they are with those in Australia recently under siege by the fiery product of a “dome of heat”, which produced four out of ten of the hottest days on record, alongside a record average maximum temperature of 40.33C. Perhaps they stray to Northern India, to the friends and family of the 170 who died as a result of a recent cold snap that brought with it the coldest day Delhi has seen in 44 years. Your thoughts might linger with the deadly Hurricane Sandy in the US, or the devastating Hurricane Evan in the Pacific. Even closer to home, Aucklanders are still suffering the ramifications of some of the most severe tornadoes they have seen in decades.
What I can guarantee is that not one of these, nor any other significant extreme weather event appearing in the news in the past few years, has passed without any comment on its relationship to climate change. And as much as I, speaking from a scientific point of view (where I would want my own grandmother peer-reviewed if I could) kind of hate the way the media blindly decides that each and every unusual weather event is DEFINITELY ABSOLUTELY AND WITHOUT A DOUBT caused solely by climate change, they are sort of on the right track.
Everyone knows that global warming, well, warms the globe. More CO2 in the atmosphere acts as a barrier for outgoing radiation, resulting in more radiation trapped at the surface – etcetera. Thankfully this phenomenon is now so well-accepted that they teach it to schoolchildren. However, this basic explanation gives somewhat of an impression that the earth will warm at a even and steady pace. And this does nothing to account for the dual extremes of wildfire-inducing heatwaves with the hottest days on record and fatal cold snaps in countries that normally see average lows of around 12-13C.
The reason I prefer the term ‘climate change’ as opposed to ‘global warming’, is that the greenhouse gas effect will result not only in increased average global temperatures, but also in increased variability in global temperatures. If average temperatures are depicted in graph form, they take on the classic bell-curve distribution as shown below, with ‘extreme’ temperatures being represented in the tail-ends of the curve with a much lower probability of occurrence. Climate change causes this whole curve to shift to the right, redefining the boundaries of ‘extreme’ temperatures, and causing ‘record hot’ weather to fall closer to the centre point of the curve and thus have a greater probability of occurring. At the same time, if we look simply at the average temperature, ‘record cold’ weather disappears entirely. And as we know from India, and from cold snaps like Europe experienced early last year, this is not entirely the case.
For the world is not a featureless and homogenous plane, and will not respond to warming all in the same way, convenient though that would be for pretty graphs and easily delivered blanket statements. Inland continental environments, already the sites of some of the most variable temperatures, could see the kind of heat domes Australia is experiencing as a common occurrence. In contrast, you also have the predicted temperature drop in Britain and Western Europe as a result of interruptions to the warm Gulf Stream current in the North Atlantic, that could occur if the freshwater : saltwater balance is altered enough by melting ice. Coastal regions will experience far less warming than inland areas, due to their proximity to the ocean and its ability to moderate temperatures and cause much more temperate climates. Furthermore, equatorial regions, having the highest receipt of solar radiation, are more likely to experience greater precipitation as a result of the updrafts caused by greater surface warming. Essentially, no two places on earth are the same, and thus cannot be expected to produce identical responses to climate change.
Therefore you get an increase in the variability of extreme weather events, i.e. a greater difference between the hottest and coldest temperatures, and an associated rise in phenomenon such as floods, droughts, fires and storms. See: climate change, not global warming.
So although the media needs to grasp a better understanding of the scientific method and stop making be-all end-all statements that aren’t supported by solid evidence, they are on the right track. And most of all, they are providing some of the most powerful material available to shift people into a mindset where they actually want to do something to stop climate change. Because storms such as Sandy, and Evan, and the images of a blackened Australian skyline, are solid visual evidence that climate change is here, now. And unless we want photos like the one below becoming one hell of a regular occurrence, we really need to start doing something about it.
Florence Isaacs is a third year geography and botany student at Otago University who hates odd socks but enjoys nerding out about science and picking a fight with climate deniers.