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, 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 already used more than half of that budget. This means that three quarters of the fossil fuel reserves need to stay in the ground, and the fossil fuels we do use must be utilized sparingly and responsibly.

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

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.

It is critical that the world captures every last bit of energy efficiency, if we are to reduce greenhouse gas emissions enough to keep below dangerous rises in temperature. I am pleased that this important new study shows how information and communication technology can play an essential role in saving energy. Now we need more and effective government policies that reward such action and penalize delayed responses.

We will move to a low-carbon world because nature will force us, or because policy will guide us. If we wait until nature forces us, the cost will be astronomical.