Once every few summers, the world meets in one of its greatest cities for a competition with roots that extend far back into history. Bravado on display, nations vie for the right to brag that their nation truly leads the pack.

Obviously, I'm talking about the Earth Summit.

Every time there's an international environment confab, it seems like countries take advantage of the moment to announce major green initiatives. Before the 2009 United Nations Climate Change Conference in Copenhagen, the United States and India announced a new partnership aimed at curbing emissions. At the same conference in Durban last year, Canada declared its intention to contribute $1.2 billion to greenhouse gas reduction.

Map of protected areas.

This year, the competition started early -- and with an impressive salvo.

In 2008, California voters approved Proposition 2, a ballot initiative that established stricter guidelines for treatment of animals in the poultry and veal industries. Most notably, the measure eliminated the use of "battery cages" for laying hens, small cages crammed with birds who are often unable to even stand. Prop 2 passed by a nearly 2-to-1 margin, despite strong opposition from egg producers across the country.

Though full enforcement of the battery cage ban wasn't mandated until 2015, many producers didn't wait to make changes. Some moved out of state. Others implemented the changes early.

A group of egg producers in this latter category have joined an unexpected crusade: a push to enact rules similar to those in Prop 2 nationally. The Los Angeles Times looked at this unexpected effort last month:

In a rare alliance, the Humane Society of the United States and egg ranchers have joined forces to lobby for federal legislation that would set national standards for egg ranches similar to those implemented at JS West [a California producer that met the Proposition 2 standards early].

"No question about it: Proposition 2 was a major wake-up call to the entire U.S. egg industry," said Chad Gregory, senior vice president of United Egg Producers, a trade organization that represents most of the nation's egg farmers.

It reads, "Participant." (Photo by Shorts And Longs.)

Congratulations, world! We did it again!

Data released by the National Oceanic and Atmospheric Administration (NOAA) indicates that land temperatures in May were the highest recorded in 133 years -- since records began. Combining land and ocean temperatures, it was the second-warmest May in recorded history -- so the encouraging news is that there's still room to grow. For now, prepare your acceptance speeches.

The NOAA report includes lots of detailed / terrifying graphs. Below, land temperatures as deviation from the average temperature between 1961 and 1990. The bigger the red dot, the hotter this May was than usual. Only Alaska, bits of Sweden, and Australia saw cooler than average temperatures.

The Washington Post reports:

With the global economy at a tipping point, a deeply divided Organization of the Petroleum Exporting Countries meeting in Vienna wrangled over whether to cut production and prop up crude oil prices.

Saudi Arabia, the world’s biggest oil exporter and the cartel member with the greatest latitude for tightening or opening its taps, arrived vowing to maintain its output and hold the line on quotas for the group. Other OPEC members, led by Iran and Venezuela, have wanted to trim output quotas to boost the price of oil.

Analysts said they expect no change in the end. ...

University of East Anglia. (Photo by mira66.)

James Delingpole is a British journalist for The Telegraph who was primarily responsible for the pseudo-controversy known by the unoriginal name "Climategate." Last month, he wrote an opinion piece mocking claims by climate scientists that they'd received death threats -- in particular, Phil Jones of the University of East Anglia.

Delingpole wrote:

Maybe it's time someone did an FOI to see whether the UEA's dodgy and discredited Phil Jones really did get any of those "death threats" he claims to have received after Climategate and which allegedly drove him to consider suicide. Speaking for myself, if Phil Jones released a report claiming that grass is green I'd feel compelled to go outside just to double check.

Simon Hopkinson did exactly that. Yesterday, the university responded.

Photo by twicepix on Flickr.

In a report released yesterday, the World Health Organization (WHO) declared exhaust from diesel engines to be a carcinogen [PDF] -- the same status as secondhand smoke. In 1989, the fumes were deemed a "probable carcinogen." The suspected culprit? Particulate matter expelled during diesel fuel combustion. Gasoline exhaust, with a different chemical makeup, remains a possible carcinogen.

As reported by CBS News, the WHO study looked at a population of 12,000 miners over the course of the past 60 years. Those regularly exposed to diesel exhaust had three times the rate of lung cancer deaths as their peers.

Actor Mark Ruffalo is taking a break from playing a big, green superhero in the movies to talking about something bigger and greener happening in New York: new solar policy. With rising electricity needs, plenty of sunshine, and a local workforce primed for jobs, New York has what it takes to lead the nation's solar economy. But the state's existing policies have installed just over 100 megawatts of solar to date. By comparison, their neighbors in New Jersey have more than six times that amount. After nearly three years of hard work - lawmakers in Albany are just steps away …

Today, New York Mayor Michael Bloomberg's office publicly released a letter signed by nearly 100 mayors from across the U.S. supporting the Environmental Protection Agency's (EPA) mercury safeguards.

From Mayor Bloomberg's release:

Cutting mercury pollution will save countless lives and help millions of Americans avoid the terrible health consequences it produces. That is why today I am proud to join nearly 100 of my fellow mayors from around the country in offering our support for EPA's new mercury standards.Twenty-two years is too long to wait for this common sense measure.

A diverse range of mayors signed onto the letter, representing big cities, small towns, and everything in between. Lots of states are represented, including coal mining states like Kentucky. I'm proud to say that the mayor of my town, Shepherdstown, West Virginia, signed the letter – maybe your mayor did, too.

If your mayor signed the letter, I hope you'll thank them through Facebook, Twitter, or letter to the editor of your local paper – you can find the full list of mayors on page two of the letter (PDF).

Believe it or not, while coal plants are our nation's #1 source of mercury pollution, until this year there were no national mercury standards in place for coal plants. None at all! Coal plants could just spew 100% of their toxic mercury into the air, which then made its way into our waterways and the fish that we eat. Expectant moms would then pass that mercury onto their babies in the womb, every year putting over 300,000 newborn babies at risk of life-long developmental problems, like lowered IQ and delays in walking and talking.

Congress required these safeguards back in 1990, but the coal industry successfully blocked them for over two decades. That loophole was finally closed earlier this year, when the EPA put standards in place that will require all coal-fired power plants to reduce their toxic mercury pollution by 90%.

As a mom, I’m thankful to these bold public officials for speaking out for public health, and I stand with them as they tell the EPA, "Clean, healthy air and water are fundamental American rights and we are eager to work with your agency to ensure these historic protections are quickly implemented."

This is what residents of the Chinese province of Wuhan woke up to yesterday.

At about 2 a.m. local time Monday morning, a dense smog began to cover the province. By early afternoon, it reached its peak density in the land-locked city of Wuhan itself.

People posted numerous photos of the haze on Weibo, the Chinese equivalent to Twitter. One blogger described her friends in the city darkly joking about being turned into Incredible Hulks.

Since 2002 the amount of wind, solar, and geothermal electricity in the energy mix throughout the world has risen from nearly non-existent levels to something that shows up in energy statistics.  Despite this important increase, these sources of electricity still count for a modest amount of the electricity in the world’s largest economies. So twenty years after the first Earth Summit in Rio, it is time that world leaders return to Rio de Janeiro, Brazil for the Rio+20 Earth Summit and step up their game on renewable electricity. Countries, companies, cities, and individuals need to commit to increasing the amount of electricity production from these sources so that they account for 15 percent of total electricity produced in 2020.

The Natural Resources Defense Council (NRDC) is releasing a new report — Delivering on Renewable Energy Around the World — which shows the progress of each of the G20 countries since 2002.  The report concludes that significant progress has been made since 2002 – when countries last met for an Earth Summit – but much more needs to be done. When leaders meet in Rio they can help unleash the potential of renewable electricity.

Some countries are rising to the top. As of 2011, the European Union (E.U.) has the most electricity produced from these sources, with Germany the most out of the G20 countries.  Other countries like the U.S., China, Mexico, and Brazil lag behind.  While all these countries have made important progress since 2002 they are still significantly behind other countries like New Zealand, Spain, Portugal, and Iceland (see map).