The very energy sources that have gotten us to where we are now are also, if we continue doing what we're doing, a shortcut to the end of all that we hold near and dear.

The Arctic is a place that historically, during all preceding human history, has largely been an icy realm with an impact on ocean currents. That, in turn, influences the temperature of the planet. The Arctic is now vulnerable because of the excess carbon dioxide in the atmosphere, with a rate of melting that is stunning.

The image of Earth from space transformed our view of ourselves. It is maybe the most important image that exists - because we can see ourselves in context in a way that otherwise would be really hard to explain. It should inspire us to wonder about it, to want to know everything we can about it and do everything we can to take care of it.

It's baffling why the issues relating to climate change - [which] have far more obvious and tangible and much more clear-cut evidence about the cause - have been slower for people to accept as a given.

Ocean acidification - the excess carbon dioxide in the atmosphere that is turning the oceans increasingly acid - is a slow but accelerating impact with consequences that will greatly overshadow all the oil spills put together. The warming trend that is CO2-related will overshadow all the oil spills that have ever occurred put together.

We don't have to be that greedy generation that just continued to take down the underpinnings of what makes the planet work in our favor.

By the end of the 20th century, up to 90 percent of the sharks, tuna, swordfish, marlins, groupers, turtles, whales, and many other large creatures that prospered in the Gulf for millions of years had been depleted by overfishing.