In 6,000 B.C.E., Earth's entire human population ( 1 ) between 5 and 20 million people. It took about 8,000 years to reach the one billion ( 2 ), yet just 100 years more to reach two billion in 1930. Eighty-five years later, that figure has more than tripled, to about 7.3 billion people today. This massive expansion has been fueled not by an increasing birth rate, ( 3 ) by a gradual extension of life expectancy and a huge reduction in infant mortality. By 2025, the United Nations projects that our global population could ( 4 ) 8.3 billion. Ninety percent of this growth will be concentrated in the poorest countries. The most dramatic increases will take place in sub-Saharan Africa, where fertility rates have remained high. Population shifts are often driven by economic forces. In the late 15th and ( 5 ) 16th centuries, Europe's conquest of the sea spurred trade, exploration and settlements across the globe. The temperate zones of the Americas were especially well-suited to their crops and livestock. Between the 16th and mid-19th centuries, millions of black Africans were brought to the Americas ( 6 ) their will by the Atlantic slave trade, victims of the New World's voracious need for labor. In the ( 7 ) nations of Europe, Japan, Canada and the United States, the trend is towards zero population growth. Birth rates have also fallen in India and China, yet 17 percent of the world's people live in India, and 19 percent live in China. In some countries, aggressive educational programs are ( 8 ) to change old-fashioned beliefs, which held childbirth ( 9 ) a woman's duty, and viewed large families as proof of wealth, fortification against hardship and security for aging parents. ( 10 ) of the factors which could limit population growth are so well planned. In the end, the environmental pressures created by the rapidly expanding population may deplete the very resources necessary for survival.

I hate to be a cynic, but I suppose it was inevitable: With consumers today increasingly willing to pay a premium for local and/or organic food, it was only a matter of time before the scam artists of the world exploited shoppers' good intentions. Just in the last couple of weeks, two separate investigations uncovered cases of organic food fraud, or at least misrepresentation. A Los Angeles television network exposed farmers' market vendors, who were lying about where and how their food was grown. Reporters bought produce at farmers' markets across Southern California, and then made surprise visits to farms where the items were supposedly grown. Most were truthful, but a few weren't: the reporters found weeds or dirt where vegetables were supposed to be growing. In one case, a vendor admitted — after the reporters followed his truck to the wholesale warehouses in downtown Los Angeles — that he sold some items he had bought wholesale as his own, including avocados from Mexico. The investigation also found produce advertised as pesticide-free that tested positive for pesticides. This sort of dishonesty isn't confined to big cities like Los Angeles. Even in my rural area, which has some good farm stands and farmers' markets, there are people who set up tables by the roadside and sell produce that couldn't possibly have been grown locally. (Plump, red tomatoes in June? Not around here.) As far as I know, they don't claim that they are selling locally grown produce. But they are taking advantage of the assumption of most people — especially tourists — that vegetables sold by the side of the road in a rural area are grown by a local farmer. The other investigation was conducted by an independent research institute that says it promotes "economic justice for family-scale farming." The group rated organic egg producers according to their animal welfare and environmental practices, and found that some looked more like factory farms, at least by the research institute's standards. In this case, part of the problem lies in the varied interpretations of "organic." As the report explains: "All organic egg producers claim to be following national organic standards, but with different working definitions and viewpoints of what the standards mean. For most consumers and many producers, organic farming means respecting underlying principles of the organic farming movement.... For others, especially industrial-scale producers, 'organic' appears to be nothing more than a profitable marketing term that they apply to the agro-industrial production system — simply substituting organic feed in their production model and eliminating harmful synthetic inputs, such as pesticides and antibiotics." The latter interpretation, even if it doesn't match consumers' expectations, doesn't necessarily equate to fraud. But in several cases, the independent research group found, farms were clearly misrepresenting their operations in their marketing.

In these days of go-anywhere adventure travel, it is possible to fly to the South Pole or crunch your way to the North Pole in an icebreaker. Our ambition, more polar bear than polar cap, took us 71 degrees north to a remote land that lies astride the 180-degree meridian in the Chukchi Sea off the northeast coast of Siberia. Wrangel Island is one of the new destinations made possible by the rapid melt of the polar icecap. Just 10 years ago, our voyage to this island would not have been possible. In 2001, the mean summer, ice-free period was 92 days; by 2010 this had increased to 135 days; by the time we arrived there at the end of August, 2011, Wrangel was completely ice free. Some scientists project that if the melt continues at the same rate as in the past 10 years, polar bears could be extinct in this region by the mid-21st century. Put another way, if you want to experience these creatures in their natural habitat, you should go sooner rather than later. So this summer we set off on the long flight east via Moscow to Anadyr. We stepped off the plane into the relief of fresh air, bright sunlight and a warm day. After a walk round the town, 50 passengers and staff transferred to the ship, the Spirit of Enderby, in several inflatable boats. Our wildlife encounters started immediately: in the strong currents of the estuary we could see the bobbing heads of spotted seals, and the flashing white bodies of beluga whales. For the next five days, as the Spirit of Enderby progressed towards Wrangel, we settled into a happy routine of morning and afternoon boat rides, shore landings and tundra walks, only twice prohibited by rough seas and wind conditions. Passing through the Bering Strait, the 80km wide channel between eastern Russia and Alaska, we continued on to anchor at Uelen, a native Chukchi village. The Chukchi are a tough people who resisted colonization by the Russians for more than 50 years and whose antecedents were among those who crossed to populate the Americas, when the two continents were joined by an ice bridge. We enjoyed seeing exquisite walrus tusk carvings, which illustrate their way of life, and examples of clothing made from skins and fur. We were entertained by a group performing traditional dances and were made very welcome. We learned how they still hunt a subsistence quota of whales and walruses in small boats and how the inland Chukchi herd reindeer. As we waved to them on our way back to the ship, a grey whale broke the surface nearby and gave us a great tail fluke display. We sailed through the night to anchor off Kolyuchin Island and awoke to the promising augurs of calm seas and patchy blue skies. The bridge announced dramatically that there were polar bears in sight on land off the port side. We clambered quickly to the top deck and watched for the next hour as a bear entertained us by ambling along the brow of a distant hill, going into a derelict wooden building and reappearing to sit on the porch before strolling off into the distance.