These effects are predictions based on climate models and on the history of previous warmer periods, many of which were unfortunately associated with major extinction events.
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Desertification and flooding Rainfall becomes concentrated in the tropics and high latitudes, while the middle latitudes become arid. Glaciers melt leading to floods initially, then desertification.
- UK Met Office Hadley Centre
forecasted in 2006 that one third of the planet will be desert by 2100, up from 3% today. Australia’s agricultural land (other than maybe Tasmania) is very likely to be included. - China’s first national report on climate change, released in late 2006, projected that national wheat, corn, and rice yields could decrease by as much as 37% in the next few decades.
- UK Met Office Hadley Centre
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Sea level Rises of one or two meters by 2100 (continuing for centuries and eventually rising over 25M).
- From Science 2008: “an improved estimate of the range of SLR to 2100 including increased ice dynamics lies between 0.8 and 2.0 M”. (The IPCC AR4 estimate was 18 to 59 cm but that ignored ice melting).
- Nature Geoscience 2007 “Seas rose 1.6 meters per century when the global mean temperature was 2 °C higher than today,” (During the
last interglacial period – the Eemian, about 120,000 years ago).
- This, along with the increase in extreme weather will make life unpleasant or worse in many of our large coastal cities, as well as contaminating the groundwater that much of their populations rely on.
- From Science 2008: “an improved estimate of the range of SLR to 2100 including increased ice dynamics lies between 0.8 and 2.0 M”. (The IPCC AR4 estimate was 18 to 59 cm but that ignored ice melting).
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Increased Extreme Weather Events It’s difficult to estimate future costs, but we must be seeing the start of this.
- Munich Re reports that the economic cost of natural catastrophes has risen 7-fold and insured losses have increased 16-fold since 1960.
- Swiss Re found that losses from natural disasters are doubling approximately every ten years.
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Increased Temperatures will damage Agriculture and marine ecosystems
- The IPCC projections, while only two years old, now look
overly
optimistic. MIT doubled their expected temperature rise in January 2009, the Hadley Centre is talking “catastrophic” 5.5 – 7.1 degree global rise in temperature. - Western agricultural systems are based on temperate climate crops which will struggle as temperatures become more tropical. Even African tropical crops are nearing their limits. This is especially important in Australia as we have a hotter and more variable climate than the norm.
- Greenhouse gas levels are already high enough to ensure coral reefs become extinct over time, which will destroy the quarter of all marine life that depends on them. We have probably already condemned the Great Barrier Reef.
- The IPCC projections, while only two years old, now look
Australia has almost certainly already been affected. The combination of decadal droughts, widespread flooding and bushfires caused by extreme temperatures are unprecedented, and are all predicted outcomes of increased warming.
On our current trend and unless you are very old or infirm I estimate that there is a small but growing chance that you will be seriously personally affected, and that becomes near certain for any child at school.
Here are two “roulette wheels” from an MIT study showing the chances of additional temperature increase dependant on our actions. The left assumes “Decisive action to reduce emissions”, while the right is “Business as usual”. The group’s lead author Ronald Prinn notes that the odds indicated by this modelling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur…
He finishes “There’s no way the world can or should take these risks”. This is very clear language and we have no excuse if we ignore it.
