[guimarin]

10% -> 2025; 20% -> 2030; 50% -> 2040; 95% -> 2050. India/Africa are included there. I think 95% of potential GHG emmissions (not just indexed to today but to 'present time') will be crossed in like 2060 or so. Renewables are going extremely quickly. we are in the steep part of the s-curve and there is no reason to believe we wont' get a few doublings due to battery cost decreases and deployed solar cost efficiencies. The transition will be a lot faster than ppl believe.

[vkou]

By that plan, we'd be looking at ~21.6 years of current GHG emissions.

This will add ~777 GT of CO2 to the atmosphere. Which will put us at ~500 ppm CO2 (We just passed 400 ppm). That would be warming between 2.5C and 3C.

If you want to hit a 95% reduction in GHG emissions, you're also going to have to:

* Shut down every single fossil fuel power plant over the next 25 years.

* Build enough renewable/nuclear powerplants to replace all of our fossil fuel power sources, twice over. (Assuming we switch to electrical transportation.)

And, the elephant in the room:

* Halve all current trans-continental shipping and air travel. It is currently responsible for ~6-7% of our GHG emissions. (And if it were to grow unconstrained, would likely double in volume in the next 30 years.)

* While bringing our other emissions down to nearly zero.

We can clearly do all this, but it would require significant changes in our lifestyles - something that optimists tend to not be willing to accept.

[themgt]

Agreed. It is more dire than most scientists are willing to admit or the public are willing to hear. At this point I think the best hope is:

a) incredibly rapid adoption of renewables

b) a Manhattan project to find a way to pull carbon out of the atmosphere starting within ~1-3 decades, once it becomes beyond obvious we've already emitted far too much and the consequences of inaction are more than human civilization can bear

[guimarin]

This is the craziest thing I've written in 2017 but: I sincerely believe we will have consumer fusion reactors by 2030 if not sooner. The work of MIT SPARC combined with graphene manufacture will make this a reality. Combine this with all the investment in battery load leveling and electric vehicles and you'll see a very rapid energy cost reduction and deployment. Probably 10 years once the design is functioning. As to the boats, these reactors are well sized for boats. My guess is ICE Air-travel will be completely eliminated for mass consumption by 2070 if not 2050, replaced by faster cheaper evacuated trains and electric short-range aircraft. The power density of li-ion batteries at roughly 350WHr/liter is not great, I'd wager we can easily get to 700WHr/liter with graphene supercapacitors utilizing a combination of 3D layering and fractal interaction. I've seen an experimental graphene supercap with fractal interaction at 1200Whr/Liter but it had a tendency to explode with only a few cycles. The normal graphene supercaps go like 100k cycles with no degradation, or 30 times longer than lithium ion cobalt (what tesla uses). We are so freaking close to cheap graphene it's ridiculous. That's the technology no one sees coming, it's just about to enter the productivity plateau. /end crazy person talk.

[Smaug123]

Graphene is cheap - you can make it with sticky tape.