As the lowest link on the marine food chain, plankton—that tiny aquatic plant, animal and bacterial matter floating throughout the world’s oceans—is a vital building block for life on Earth. Besides serving as a primary food source for many fish and whales, plankton plays a crucial role in mitigating global warming.

Indeed, the ocean is the world’s largest "carbon sink": As much as one-third of man-made CO2 emissions are stored in the oceans and therefore do not contribute to global warming. This is because its plant component, phytoplankton (its animal component is called zooplankton), pulls massive amounts of carbon dioxide (CO2) out of the atmosphere as it photosynthesizes.

But various environmental factors are taking their toll on plankton the world over. The U.S. National Oceanic and Atmospheric Administration (NOAA) reported recently that marine phytoplankton is declining across the oceans. Even Canadian cod fishermen are noticing that the plankton-feeding fish they catch are often nearly starving as a result of lack of this crucial food source.

A 2007 study published in the scientific journal “Nature” found that human-caused increase in CO2 pollution is altering the pH (acidity) levels in the oceans. This change in chemistry is expected to have adverse effects on the entire ecosystem. More acidic ocean water inhibits the ability of shell-forming marine organisms—from plankton to mollusks to corals—to form properly. Smaller and less healthy populations of plankton would be bad news for all the other creatures above it on the ocean’s food chain.

Higher water temperatures, also attributable to our fossil fuel addiction, can also have a devastating effect on plankton. A recent report in the Journal of the Marine Biological Association of the United Kingdom noted that, in the Adriatic Sea cooler winter conditions — which are less frequent in a warmer world — are needed for plankton production and nutrient availability. Furthermore, warmer sea temperatures can cause "blooms" of other sea life (such as happens with algae), resulting in oxygen starvation in the water, a condition that is devastating to plankton and other marine creatures and organisms.

In other situations, blooms of phytoplankton themselves—the tiny plants can gorge on the nutrients from the run-off from farms and lawns on land—can lead to oxygen — starvation in the water. "The decomposition of these multitudes of phytoplankton removes oxygen from seawater, creating oxygen-poor ‘dead zones’ where fish cannot live," reports Carly Buchwald, a researcher at Woods Hole Oceanographic Institution.

Satellite imagery shows that these "dead zones" are expanding. Some scientists are advocating "iron fertilization" — the spreading of large amounts of iron across the world’s seas—to spur plankton growth. But others worry that such tinkering with complex ecosystems could have potentially harmful effects.

Adam Cohn, courtesy Flickr.

Decades of rapid-fire development and lack of government oversight has meant that China now faces some serious environmental challenges. According to research by the Netherlands Environmental Assessment Agency, China surpassed the United States as the world’s leading emitter of greenhouse gases in 2006″"and hasn’t looked back. (While the Chinese emit some eight percent more carbon dioxide than their American counterparts, the U.S. still leads the world in greenhouse gas emissions per capita, due to its significantly smaller population size and higher standard of living.)

Beyond its contribution to global warming, China is also a world leader in other forms of pollution, given its huge population and its ambition to become the next international economic superpower. According to the World Health Organization (WHO), current levels of air pollution in China far exceed international environmental standards. A recent analysis found, for example, that the air in some four dozen Chinese cities contained as much as seven times as much particulate pollution”"which can get lodged in human lungs and cause a wide range of health problems”"as deemed safe by WHO.

But critics say blaming China for its rampant pollution is unfair, given all the manufacturing the world’s developed countries outsource to Chinese companies. Qin Gang, China’s foreign ministry spokesman, refers to China as the “world’s factory” and says: “A lot of what you use, wear and eat is produced in China”¦ “On the one hand, you increase production in China; on the other hand you criticize China on the emission reduction issue.” Yang Ailun of Greenpeace China agrees: “All the West has done is export a great slice of its carbon footprint to China and make China the world’s factory.”

Despite its efforts to go green, China still depends on coal”"the dirtiest of all the fossil fuels”"for some two-thirds of its energy needs. Chinese officials have strenuously opposed the binding limits on greenhouse gas emissions set by developing countries, arguing that already industrialized nations are to blame for most of the emissions already in the atmosphere.

According to Isabel Hilton, a journalist with the UK’s Guardian, industrialized countries should feel an obligation to shoulder at least some of the burden of helping China become a greener nation. “This means drastically reducing our own emissions and helping China with the finance and technology required to move to a sustainable, low-carbon economic system.”

There is progress afoot: Meetings between top Chinese and U.S. officials earlier this year led to the creation of a joint research center to address issues related to clean energy, with each country contributing $15 million to pay for initial research efforts.