To quote Martin Lack, here is a summary of the problems we are now facing:
- The Earth’s current energy imbalance is 0.6 Watts per sq.m.; a rate of energy input 20 times greater than the energy output of all human activity; and equivalent to the detonation of 400,000 Hiroshima-type atomic bombs every day.
- Since measurements began in 2003, there has been a noticeable acceleration in the annual rate of mass loss from both the Greenland and Antarctica ice caps.
- The last time atmospheric CO2 was 390 ppm, sea levels were 15 m higher than they are today, which implies even if we stopped burning all fossil fuels tomorrow, this is where they would end up several centuries from now because the warming “is already in the pipeline” (i.e. because the Earth must warm-up in order to restore its energy balance).
- Unless we stop burning fossil fuels soon, sea level rise will continue to accelerate, which is likely to cause between 1 and 5 metre rise by 2100AD depending on how quickly we stop.
- Palaeoclimatology tells us that 350 ppm is the safe limit for avoiding significant disruption to the planet’s ecological carrying capacity (i.e. in terms of both populations of individual species and overall biodivesity); and it now seems likely that between 20%-50% of all species will be “ticketed for extinction” by the end of the century.
- If we push the Earth beyond it’s “tipping point” (i.e. allow all the emerging positive feedback mechanisms to take hold); ACD will become unstoppable; and the ensuing socio-economic damage will be almost unimaginable. The total global cost of mitigation is already put at somewhere between 35 and 70 Trillion US Dollars depending on how soon we choose to act.
- If we had started to get off fossil fuels in 2005, it would have required 3% reduction per year in order to restore energy imbalance by 2100AD. If we start next year, it will require 6% p.a. If we wait 10 years it will require 15% p.a.
- Recent droughts in Texas, Oklahoma and New Mexico were 3 Standard Deviations outside the norm. Events such as these cannot therefore be ascribed to natural variability; anthropogenic climate disruption (ACD) is happening just as Hansen said it would 24 years ago (if we did not change course – which we haven’t).
- Pursuing emissions limits (i.e. Cap and Trade) will not work because there is no actual incentive to reduce emissions without any self-imposed restraint being to the advantage of others who do not do the same (i.e. the Tragedy of the Commons problem).
- Hansen uses the analogy of an approaching asteroid – the longer we wait to prevent it hitting us the harder it becomes to do so.
The Earth is warming, it is because of us and it will be bad.
Every day we delay in addressing the threat makes the bad outcomes worse.