On September 21, people from all over the world will take to the streets to demand action from their leaders to address the looming climate crisis. I will be one of them.

Heads of State -- along with business and civil society leaders -- will gather in New...

Nearly 30 years ago I led a campaign to save Antarctica. It was one of the best things I've ever done - because we won! It started when the Antarctic Treaty States decided to negotiate an agreement to allow oil, gas and minerals extraction, and ended with a 50-year moratorium...

Too late or not too late? That is the question which anyone could be forgiven for asking after reading the news about the groundbreaking climate report (PDF) released yesterday by the Intergovernmental Panel on Climate Change (IPCC).

It is now beyond a shadow of a doubt that climate...

Deep down inside, do people want what's best for themselves, or what's best for everyone?

This question lies at the heart of my current escapist-reading-before-bed novel Next History: the Girl Who Hacked Tomorrow.

The novel's 20-year-old heroine stakes her salvation (and that of humanity as a whole) on the...

This post is co-authored by Kelly Rigg and Emily Saari, a writer and researcher for TckTckTck.org.

I'm pleased to be co-hosting an awards ceremony this week celebrating global 'momentum for change' at the United Nations climate talks in Warsaw.

So far, the...

Maybe I've lived outside the U.S. too long, or maybe my mind is just totally focused on the start of next week's international climate talks in Warsaw. But I think I may have been the only one who reacted somewhat cynically to last week's news that President Obama had signed...

It was an inspired idea -- bring together 100 of today's boldest women leaders in sustainability, and see if they can produce an accelerated, gender-aware climate action agenda which can be implemented everywhere, from households and communities to boardrooms and negotiation halls.

One of its organizers, Osprey Orielle...

During the Pacific Island Forum, Australia, New Zealand and 13 Heads of State from other Pacific nations made a landmark declaration -- calling for the full phase-out of greenhouse gas pollution, acknowledging that current efforts to tackle climate change are insufficient.

The Majuro declaration for Climate Leadership is surprisingly strong considering these types of documents are usually intent on satisfying the least ambitious parties -- Australia and New Zealand, in this case. But the text, adopted at the 44th Pacific Island Forum, appeals for urgent action, commits all signatories to be "climate leaders" and calls for an energy revolution.

For me, two things stand out in particular.

First, the declaration explicitly recognizes the need for a complete "phase down" of greenhouse gas emissions. Not "x% emissions by date y" -- the sort of language that is important from a scientific perspective but has little meaning for the general public. The idea of a phase down makes clear that in the long run we need to eliminate greenhouse gas pollution altogether.

This implies that we must stop investing in the development of new sources of fossil fuels, or new infrastructure such as coal-fired power stations that lock in greenhouse gas pollution for 50 years or more.

It implies that we need to stop subsidizing our continued dependence on fossil fuels. For every dollar we spend subsidizing renewables, we spend six subsidizing fossil fuels. Fatih Birol, chief economist for the International Energy Agency, calls fossil fuel subsidies "public enemy number one." And it implies that everyone must do his or her part to achieve not just a lo- carbon future, but in the long-term a net-zero one.

Second, the declaration recognizes the complete insufficiency of current efforts to address climate change, and accepts a collective responsibility to act with urgency. It demonstrates that many Pacific Island states already have ambitious plans to transition away from fossil fuels, and calls on others around the world to follow their lead.

In essence, the agreement reframes the "I won't move till you move first" stance we've come to expect at the United Nations climate negotiations, to one of "I'm moving ahead and I invite you to move with me." Given that many countries are doing more at home than what they are prepared to commit to in the context of the negotiations, this kind of approach could be a game...

For the 16 nations that are member to the Pacific Islands Forum (PIF), climate change is not a hypothetical problem, but a looming crisis. Their Heads of State are gathering this week in Majuro, the capital of the Marshall Islands, to adopt the Majuro Declaration for Climate Leadership.

If they...

When an email from Tony Leiserowitz popped up on screen the other day, I was blown away to read the findings of his team's latest national survey of U.S. opinion on climate change:

"One in eight people (13%) say they would be willing to personally engage in...

One year ago today, Australia joined a rapidly growing list of nations in putting a price on carbon. It was a historic day for climate action down under, but it is possible that this infant policy may not get a second birthday.

Prior to -- and since -- its inception,...

Here's a question I bet no one has ever asked before: What do Mary Poppins and the International Energy Agency have in common?

Answer: Both like to dish out their medicine with a spoonful of sugar. At least that's my take on an important new report released by...

Marjan Minnesma may be the most inspiring person you've never heard of, unless you live in the Netherlands as I do. A few years ago, Marjan got fed up with waiting on governments to act. As a citizen of a small, industrialized country -- blessed with resources but riddled with...

Carbon logic dictates that if President Obama is at all serious about addressing climate change, he must help put an end to Canada's tar sands folly, and say no to the Keystone XL pipeline.

Leaders of the world's governments made a commitment to us more than 20 years ago. They...

As a small team of youth ambassadors for Greenpeace's Arctic campaign begin their trek to the North Pole, I'm reminded of the campaign to save the Antarctic (video), which I led on behalf of Greenpeace in the 1980s.

While politics between the two poles are literally...

A report published today by Europe's Health and Environment Alliance (HEAL) is a powerful wake-up call about the dangers of coal-fired power. The Unpaid Health Bill: How Coal Power Plants Make Us Sick claims to provide the "first ever economic assessment of the health costs associated with air...

Alberta's tar sands lobbyists must be earning a fortune these days.

So much dirty oil, and so few pathways to market. Their opponents have successfully blocked several of those pathways for the time being, forcing the beleaguered Canadian province to fight a battle on multiple fronts. And those who think...

"What gives you hope? This is a question I'm often asked these days. And what I've come to realize is that being hopeful, in the face of so much bad news about climate change, is not something that just happens -- at least not to me. It's not a passive...

There's a sign hanging at Muir Woods, a gorgeous redwood forest not far from San Francisco, which reads:

"In 1945, delegates from all over the world met in San Francisco to establish the United Nations. On May 19, they traveled to Muir Woods to honor the memory of President Franklin...

Like the Ghost of Christmas Future, the World Bank has just provided us with a frightening glimpse into our world-to-be if, unlike Scrooge, we fail to change our ways.

The year is 2100. Governments have failed to heed the increasingly urgent warnings 100 years back to drastically reduce CO2 emissions...