For those of us in the northern hemisphere, today is the longest day of the year. Here in Oakland, California, we’re soaking up over 15 hours of sunlight. Globally, about 7600 exajoules of solar energy—that is, about 15 times the amount of energy humanity will use this year—will reach the earth’s surface in the next 24 hours, powering everything from phytoplankton to redwoods to backyard BBQs.

It is, in other words, a beautiful day to get outside and celebrate the power plant that has kept our planet humming with life for the last 3.7 billion odd years.

It’s also the perfect day to celebrate what we’re learning to do with the sun’s power. The past few years have ushered in an unprecedented, unforeseen, and largely unheralded solar energy revolution. As recently as 2005, global installed solar power capacity stood at 4.5 gigawatts (GW). Today, the figure exceeds 65 GW, which is equivalent to the capacity of about 130 average-sized coal-fired power plants.

To put recent growth of solar power in perspective it helps to look at how it has played out in particular places. Take the U.S., for example. Solar is America’s fastest growing industry, and already employs more than 100,000 men and women—more than U.S. steel production and more than U.S. coal mining. In California, which leads the nation on solar power, the number of installed solar energy systems has increased from about 500 in 1999 to more than 50,000 in 2011. These days, when you fly into a place like Oakland, you can see your plane reflected in the rooftops below.

Then there’s Germany. A few weeks ago, every energy wonk in the world did a double take after learning that the country had met a third of its weekday noontime electricity demand—and half of noontime electricity demand on a Saturday—with solar power. These statistics are amazing in of themselves, but even more amazing is the fact that three-quarters of Germany’s solar energy capacity is locally-owned. Put simply: the world’s fourth largest economy and seventh largest energy consumer is now meeting a huge chunk of its electricity demand via clean energy sources whose economic benefits flow to everyday people.

So what’s driving the solar revolution?

Better, cheaper solar technology is a big part of it. While the efficiency with which solar cells convert sunlight to usable energy has improved dramatically over the last few decades, manufacturing costs have come down. The upshot of both these trends is that the cost per watt for solar panels declined from $22 in 1980 to well under $1 by January of this year.

Policy has also played an important role. Many countries, Germany included, have implemented feed-in tariffs that essentially subsidize solar and other forms of renewable energy. In the U.S., government support for renewable energy has been more scattered, but state and federal incentive programs have still played a critical role in expanding the solar industry. For a fraction (one twelfth, to be precise) of the government dollars that go to the fossil fuel industry, these programs are driving innovation, bringing us closer to the day when solar will be cheaper than coal, even absent incentives. In California, we are already arriving at that point.

Finally, a new breed of solar entrepreneur is bringing down the costs associated with installing and financing solar power. One major innovation came from Jigar Shah, a founder of SunEdison, who realized that it might make more sense for many property owners to lease, rather than purchase, solar energy systems for their roofs. Thanks to solar leases, building owners are now able to go solar with no upfront cost and make lease monthly payments that are typically less than what they would pay the utility for the same amount of energy. More recently, innovations in cleantech have been merging with innovations on the net to form what Sunil Paul calls the “cleanweb.” Sungevity uses advanced software and satellite imagery to provide potential customers with iQuotes for solar installations on their roofs. My own company, Solar Mosaic, is using the web to empower people to pool their resources to create solar in their communities. Our efforts recently won us a $2 million grant from the Department of Energy’s Sunshot Inititiave, which aims to catalyze a dramatic decrease in solar energy costs over the next decade.

There are plenty of days in the year to think about the mistakes we’ve made fighting climate change and how much we have left to do to create a society powered by clean energy. Yet, for now, with the sun shining outside, it’s worthwhile to step back and think about what we have accomplished. It’s worthwhile to think about all of the solar panels that are out there catching some serious rays today and how much coal–about 186 million tons per year–they’ll keep in the ground.

What comes next? According to McKinsey and Co, the revolution is just getting started: we’re on track to reach 400-600 GW of global solar capacity (that is, the equivalent of between 800 and 1200 coal-fired power plants) by 2020. Other projections estimate that by the end of the decade solar will be the cheapest power source for more than 80 million Americans. Some would say these projections are overly optimistic. I suspect we can do better than the projections suggest. We’ll have to work hard. We’ll have to innovate like crazy. We’ll have to beat some seriously big and bad opponents and overcome some immense challenges.

Fortunately, we know can do all of this, because we’re already doing it.

This post was crossposted from the Huffington Post.

Today is “Young and Future Generations Day” here at the International Climate Negotiations in Copenhagen, and I'm here with my wife Wahleah and our two-year-old daughter Tohaana. Along with thousands of other young people, we're doing everything in our power to convince world leaders to commit to a fair, ambitious, and legally binding international agreement based on a target of 350 parts per million (ppm), which is the safe upper limit of carbon dioxide in the atmosphere.

Less than 400 miles away in Oslo, Norway, President Obama is accepting the Nobel Peace Prize “for his extraordinary efforts to strengthen international diplomacy and cooperation between peoples.” If ever there was a time and place to live up to that honor, now, in Copenhagen is it.

We fight, even against insurmountable odds, because sometimes we win.

As I get ready to head to Copenhagen this Saturday for the international climate negotiations, I'm thrilled to see the success of The Leadership Campaign and their efforts to have Massachusetts use 100% clean electricity by 2020.

On Monday, Representative William Brownsberger will file their bill, An Act to Re-power Massachusetts, in the Massachusetts House, calling on Gov. Deval Patrick to create a task force to formulate a plan to get Massachusetts to100% clean electricity by 2020.

by Rinku Sen & Billy Parish

Last week, the Labor Department reported that youth unemployment stands at 18.2%, nearly twice the national average of 9.8%. The percentage of young people without a job is a staggering 53.4 percent, the highest figure since World War II. Looking deeper, the statistics for youth of color are terrible and telling.

According to the most recent data released by the Bureau of Labor Statistics, 40.7% of black youth between 16-19 are unemployed, almost double the amount of whites teenagers (23%). For Latinos the same age, the rate is nearly 30%. Get a little older and the gap grows wider. Unemployment for black Americans aged 20-24 is 27.1%, over twice that faced by white youth (13.1%) in the same age range.

The glaring differences indicate that unemployment is not only decidedly raced, but also that the current economic condition is wholly unforgiving for young people of color. Only a massive, well-funded set of green jobs programs explicitly designed to close those racial gaps can create a truly vital, full-employment economy.

The New York State Senate and Assembly, too often a model of corruption and dysfunctionality, rose above petty politics last week to pass forward-thinking legislation on climate and energy, setting a precedent for bipartisanship and a sensible cap and trade system.  The State Senate passed the groundbreaking Green Job/Green New York Act, with strong support from Republicans, Democrats, and the Working Families Party, which spearheaded the legislation. The bill — expected to be signed into law this week by Gov. David Patterson leverages $112m in revenue from the Northeasts's Regional Greenhouse Gas Initiative (RGGI) into $5 billion of private investment to finance home weatherization, energy efficiency projects, and green jobs creation.

Eight years ago today, two planes flew into the World Trade Center, another crashed into the Pentagon, and a fourth landed in a Pennsylvania field. The raw power of that day came to be symbolized by a date composed of three numbers. Three numbers that evoked the shock of being attacked, the horror of the sounds and images on our television sets, and the heroism of so many men and women. Three numbers that framed the events of the last decade and seemed like they would define my generation.

But eight years ago, many in my generation couldn’t vote. We didn’t choose the President, his wars, or his policies. In fact, young Americans have largely rejected the politics of fear and division that dominated those formative years of our political consciousness—voting 2 to 1 in favor of Barack Obama. Today we remember the victims and honor our heroes, but we also have a new President, new crises, and three new numbers: 3-5-0. 350.

It can if that number is 350. That's the safe upper limit of carbon dioxide in the atmosphere: 350 parts per million (ppm). It’s also the rallying cry of a creative campaign to raise awareness of the climate crisis and build grassroots support for the 2009 Climate Conference in Copenhagen. 350.org wants communities around the world to join together on October 24 for an International Day of Climate Action. You can join with your church, your school, or your friends and do something to visibly get the word out about 350. [See the latest video from 350.org]

Wednesday was the 39th anniversary of Earth Day and to mark the occasion, President Obama was in Newton, Iowa to speak about clean energy. Newton is one of those towns where most of the residents are employed by one major employer, and until October 2007, that employer was Maytag. So when Whirlpool bought Maytag and shut down the Newton plant, over 12% of Newton's 16,000 residents lost their jobs. If you didn't lose a job, your husband, sister, or neighbor surely did.

But now Newton's a shining example of what's possible. Instead of dishwashers and washing machines, the people of Newton are making wind turbines. That's why President Obama chose Newton and Trinity Structural Towers to argue that “the choice we face is not between saving our environment and saving our economy.  The choice we face is between prosperity and decline.”

But towns like Newton aren't just losing jobs, they are losing talent too. Young people have been hit hard by this recession. According to the Education and Labor Committee, of the 1.2 million jobs lost last year, 60 percent were held by workers under the age of 25. Mobile and in search of opportunity they are moving to bigger cities and mega regions that promise greater opportunity. Iowa, in particular, has been hurt by this “brain drain,” losing more college graduates than any other state in the country.

So while we replace dishwashers with wind turbines, and re-open empty auto manufacturing plants with solar manufacturing facilities, let's also work to build truly whole communities. The communities that define themselves by one industry or one employer will be increasingly at risk. A healthy, 21st century economy demands that we become increasingly self-sufficient in the resources we use—the food we grow, the water and energy we consume, and the products we build. Revitalizing local living economies can create jobs, conserve energy, and keep young talent in the community.