By Steve Newman : EarthWeek: A diary of the planet

The impact humans have made on the surface of the planet has become so expansive that scientists say Earth has entered a new epoch — the Anthropocene. A team from the Geological Society of London made the determination after examining transformed patterns of sediment, disruptions to the carbon cycle and wholesale changes to the world's plants and animals. Members believe humans have so physically changed the landscape that post-industralized Earth can no longer be considered still in the Holocene epoch.

Earthquakes

The year's most deadly earthquake struck China's Sichuan province with a magnitude of 7.9, killing at least 69,000 people. The May 12 disaster forced 15 million people to be evacuated, while more than 5 million were left homeless by destruction estimated at $86 billion.

• Hundreds perished in Pakistan's Balochistan province on Oct. 29 when a 6.4-magnitude quake struck near the provincial capital of Quetta.

• Deadly quakes also occurred in southern Peru, East Africa's Great Rift Valley, Kyrgyzstan, western Sumatra, northern Japan, and along China's Sichuan-Yunnan border.

Crisis of Humanity

Food riots in several poor nations during March and April caused U.N. and other officials to consider that the growing diversion of grain harvest from food to ethanol fuel was causing a global food crisis. Dominique Strauss-Kahn, head of the International Monetary Fund, says a growing number of government ministers had labeled the impact of biofuels as a "crisis of humanity."

Nature Overwhelmed

U.S. scientists said that human activity has overwhelmed an eons-old mechanism that Earth uses to keep the atmosphere's carbon dioxide (CO2) content in balance. Writing in the journal Nature Geoscience, co-author Richard Zeebe says that the mechanism, known as "feedback," has been thrown out of whack by a steep rise in carbon-dioxide emissions. He says the process in which CO2 is removed from the air by the weathering of mountains and washed into deep-sea sediments has been hobbled by human activities.

Tropical Cyclones

The worst natural disaster in Myanmar's history occurred when Cyclone Nargis roared ashore from the Bay of Bengal on May 2. The most deadly named cyclone of all time in the North Indian Ocean basin caused more than 146,000 fatalities and inflicted catastrophic damage.

• Typhoon Fengshen left more than 1,354 people dead in the central Philippines and China's Guangdong province between June 20 and 24.

• Hurricane Gustav killed 138 people across the Caribbean and the U.S. Gulf Coast Aug. 24-Sept. 3.

• Ike became the third-most destructive hurricane to ever strike the United States. It devastated parts of the Texas Gulf Coast after inflicting severe damage to Haiti and the entire length of Cuba Sept. 7-13.

Eruption

The southern Chilean city of Chaiten was made uninhabitable by the first eruption of a nearby volcano in at least 9,000 years. Ash blowing across Patagonia during May from Chaiten Volcano poisoned crops, pastures and water supplies.

Arctic Meltdown

The Arctic polar ice cap melted at an unprecedented rate, opening up both the famed Northwest Passage and the Northern Sea Route off northern Russia simultaneously for the first time on record. In a trend that began in the mid-1960s, 2008 was the second-warmest year in the Arctic, closely behind the record set in 2007, which produced the greatest Arctic meltdown ever observed.

Solar Cycle 24

An eerie calm between sunspot cycles ended in early November as four of the first sunspots of the next 11-year period of solar activity finally appeared. The sun had been relatively free of any new spots since the previous cycle ended last year. The new cycle is the 24th since solar observations began in 1755.

Non-Human Rights

Two separate European nations granted unprecedented rights to members of the animal kingdom. Spain declared that monkeys and apes ("our non-human brothers") may not be killed or arbitrarily deprived of their liberty. New Swiss regulations make it illegal to flush live goldfish down the toilet. Fishermen may no longer practice catch-and-release fishing, and the use of live bait is prohibited. Pets such as parrots and hamsters may no longer be kept by themselves, and livestock such as sheep and goats must have at least "a visual contact with their fellows," under the new laws. A Swiss federal committee proclaimed that plants deserve respect, and killing them unnecessarily is morally wrong.

By Steve Newman