When you have a vision of where you need to go, it sounds utopian. But when you get to the tipping point, your understanding switches.

We are just about to cross the 400 parts per million threshold.

No architect should design buildings that import a huge amount of energy.

The fact that solar has gone down 80 percent since 2008 is astonishing. Wind is perhaps not coming down as quickly. Lack of storage - batteries - is a bottleneck. That makes it very difficult to put large amounts of renewable energy on the grid.

We shouldn't have stupid cars that use liquid fossil fuels. Come on, how outmoded is that? We have to get to the point where this is no longer a part of our experience.

Carbon neutrality is going to be so standardized that you will look at anything that is not carbon neutral and go, where the hell did that monster come from? It's exciting.

In a perfect world global emissions would have peaked already. In a semi-perfect world we will peak on Dec. 31, 2020. The fact is, that's going to be difficult. We know that it's going to get more and more expensive the longer we delay.

The record-breaking extreme weather events causing chaos across the globe should be a wake-up call. The transition to a low-carbon economy will be much more painful if we wait until there is a climate crisis before recognising that more than half of the world's fossil fuel reserves will have to remain in the ground.

Each building should produce as least as much energy as it's going to need, and have more to put on the grid. They should be using all of the natural light and natural heat.

Quite frankly, there is no answer to climate change without substantially, dramatically, increasing the amount of renewable energy in the global energy system.

We're going to get to the point where we ask how the hell we put up with high carbon for so many years. You thank your lucky stars, because you are seeing this transformation in your lifetime. You are going to tell your children and your grandchildren you saw this whole thing in front of your eyes.

DEMAND, PURCHASE & USE LOW CARBON PRODUCTS AND SERVICES. MAKE LOW CARBON SEXY!

We, the older generations, simply cannot leave a world for you, the younger generations, in which climate change impacts become ever more threatening to your survival. Still more public attention and action are needed. Solutions like renewable energy or energy efficiency need to fully power our collective future!

We have to get to the point where each individual, each corporation, each community chooses low carbon, because it makes fundamental sense. It should become a no-brainer.

Connect with people, visibly and loudly showcase initiatives that reduce greenhouse gases emissions, nurture youth leaders, or spread the message by raising awareness through campaigns. I am convinced that your contributions will ensure that climate change solutions safely power our - and especially your - future.

Second, I believe in human ingenuity – that when we decide on a task to be done, no matter how daunting it may seem at the beginning, we are able to unleash human ingenuity and human innovative capacity that was unknown, and takes us to a solution.

Think global, act local.