The Pacific Yew can be cut down and processed to produce a potent chemical, taxol, which offers some promise of curing certain forms of lung, breast and ovarian cancer in patients who would otherwise quickly die... It seems an easy choice - sacrifice the tree for a human life - until one learns that three trees must be destroyed for each patient treated.

...2009 saw the eighth 'ten-year flood' of Fargo, North Dakota, since 1989. In Iowa, Cedar Rapids was hit last year by a flood that exceeded the 500-year flood plain. All-time flood records are being broken in areas throughout the world.

In digital era, privacy must be a priority. Is it just me, or is secret blanket surveillance obscenely outrageous?

I have felt for a long time that the pathway to solving the climate crisis is through the building of a massive grassroots army of men and women who will go out there and win the conversation on climate, and persuade businesses, and universities, and towns to switch to renewable energy and to reduce emissions. And the big change from ten years ago is that people are way more receptive, not only to the message that we have to act, not only to the message that now we can act, we have the solutions now - that's the biggest change - but also willing to make a commitment that we will act.

During my service in the United States Congress, I took the initiative in creating the Internet. I took the initiative in moving forward a whole range of initiatives that have proven to be important to our country's economic growth and environmental protection, improvements in our educational system.

Eventually we'll use a CO2 tax offset by a reduction in taxes elsewhere alongside a cap-and-trade plan, but the degree of difficulty associated with a CO2 tax far exceeds that with a cap-and-trade plan. We're seeing it's hard to get a cap-and-trade plan and it's much easier to use as a basis for a global agreement than a CO2 tax.

Earlier in this century, the Heisenberg Principle established that the very act of observing a natural phenomenon can change what is being observed. Although the initial theory was limited in practice to special cases in subatomic physics, the philosophical implications were and are staggering.