The Effects

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.

• 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.
• 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.
    

• Increased Extreme Weather Events It’s difficult to estimate future costs, but the unprecedented floods, heatwaves, bushfires and wild weather in 2010/11 is clearly the start of this.
  • Munich Re’s natural catastrophe database, which is the most comprehensive of its kind in the world, shows a more than threefold increase in loss-related floods since 1980 and more than double the number of windstorm natural catastrophes. They state “The only plausible explanation for the rise in weather-related catastrophes is climate change”
  • Respected meteorologist Jeff Masters said “In my thirty years as a meteorologist, I’ve never seen global weather patterns as strange as those we had in 2010. The stunning extremes we witnessed gives me concern that our climate is showing the early signs of instability”
• Increased Temperatures will damage Agriculture
  • The IPCC projections, while only a few 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.

• Ocean Acidification, warming and sea level rise will damage Ocean Ecosystems
  • 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.
  • John Veron an Australian expert on corals predicts that 600 ppm leads to no coral occurring shallower than 10 metres, extinctions will be extensive, reefs will be highly erosional, coralline algae which hold the reefs together won’t exist, there will be major impacts from sea-level rise and super-cyclones.
  • At 800 ppm there will be no reefs, molluscs will be in sharp decline and there will be huge biodiversity loss. Further concentrations lead to a mass extinction as per the KT boundary.

Australia has almost certainly already been affected. The combination of decadal droughts, massive 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.