I think it’s a given that every year the planet uses more electricity, and I don’t imagine that that is going to change anytime over the next century or two.
Even with rising energy efficiency of devices and machines, there’s still going to be a maximum value after which it becomes waste heat. At about what point of yearly power, continuing out the current graph of useage, are we going to start seeing global warming occur due to this phenomenon?
According to this article, the current energy imbalance is 0.58 watts per square meter and the surface area of Earth is 510 million square kilometers, or 5.1 x 10^14 m2, which gives 2.96 x 10^14 watts of energy gain (296 terawatts). For comparison, global energy consumption was 15 terawatts in 2008, which is equivalent to about 5% of the trapped heat from global warming (0.029 w/m2). For another comparison, observed solar variation since 1975 is about 0.25 w/m2 (around 0.2 w/m2 over a single solar cycle); the 0.58 w/m2 was during a deep solar minimum so the longer term value is closer to 0.7 w/m2. I doubt that we will ever actually use enough energy to get close to those figures; we are talking about an order of magnitude increase; even if everybody had a U.S. lifestyle it wouldn’t get that high.
Going by this chart, power consumption has been growing at a fairly linear rate since, say, 1957. That seems to be an increase of ~40 quad BTUs per 35 years. If our current usage is 115 quad BTU, then it would take (1150-115) / 40 * 35 = 905 years to increase by an order of magnitude.
So in 2912, this will start to become an issue, you’re saying?
I’m pretty sure that by 2912 there will be no fossil fuels left and we’ll be dependent on renewable energy sources, unless we finally develop practical fusion (always 20 years away…), which means that there will be no net energy input to the environment (since renewable energy just captures what is already in the environment). Add to that a expected peak or at least plateau in human population within this century of 20-30% higher than today and that one person can only use so much energy, even an American (speaking of which, consider this chart, admittedly only oil use but the U.S. is by far the largest oil consumer).
I’m pretty certain that it’s irrelevant whether we’re using coal or cold fusion to power things. Waste heat is going to happen either way once you actually go to use the energy.
We obey the law of thermodynamics in this thread.
The current best estimate is about 50 years. And if we haven’t got it by 2912, then we deserve to go extinct.
