Alvaro del Campo

Thursday, Nov. 11

You can learn a lot muddling around a forest in the middle of nowhere, but you also learn a lot once you’re back in the city catching up on your e-mail.

In the field we worried about why it was raining so little. Back in Iquitos, Peru, we discovered that our field work had coincided with the worst drought ever recorded in the Amazon basin. Reading the previous two-and-a-half weeks of e-mail, it was possible to track the drought’s progress through the newsletters I receive every few days from a Brazilian research institute.

First there was a note saying that the river level gauge at Manaus was at the twelfth lowest stage in recorded history. A few days later, a note said it was at the second lowest stage in history, and then, on Oct. 26, a note confirmed that the river had dropped to the lowest recorded level since measuring began 108 years ago.

That was the same day we arrived at our third camp, where the Yaguas River was 23 feet below its floodplain and the tributary next to camp had practically run dry. The low readings at Manaus did not make front-page news back home, but maybe they deserved to: Two of the three worst Amazon droughts in history have now occurred within the last five years,­ the sort of coincidence that also turns up in conversations these days about icebergs and hurricanes and Siberian heat waves.

But the drought was definitely news in Iquitos, where people were deeply upset by the lack of rain. It was unsettling, too, for our little band of biologists to be writing about the drought on laptops powered by Iquitos’s gas-fired power plant, located in a part of Peru where roughly half of the landscape is currently inside oil and gas concessions.

Zaleth Cordero

Long dry spells like these in Amazonia wither crops and worsen air pollution and cut off whole towns from the rest of the world, when the arm of the river they’re on turns to mud. They also destroy forests. Scientists used to think that if the guys with chainsaws could be convinced to stop cutting down trees, tropical deforestation would just stop. We now know that if all the guys with chainsaws stopped cutting down trees tomorrow morning, Amazonian forests might disappear anyway, thanks to higher temperatures, droughts, and forest fires. Guys with chainsaws, meet guys with laptops (and air conditioners, station wagons, and blogs).

But there was some good news in the inbox, too. While we were in the field, the Peruvian government had declared a large new park west of Iquitos, which will protect a wonderful wilderness area along the Peru-Ecuador border.

This means that more than 15 percent of Peruvian territory is now inside protected areas ­— a hugely important achievement worthy of celebrating during what remains of the United Nations’ International Year of Biodiversity. Some of the same government employees responsible for establishing that new park were at the presentation our team gave in Lima, and their enthusiasm for the results of the trip was extremely gratifying. Going forward, it will be they — the Peruvian parks service, the foreign service, and ministry of the environment, together with local communities — who determine the best way to conserve the stunning wild landscape of the Yaguas River valley.

Our trip would not have been possible without the support of the indigenous communities, who welcomed us into their homes along the Putumayo River and worked alongside us in the field. We also received invaluable support from Peru’s protected areas service and national police, as well as from museums in Iquitos and Lima. The work was funded by the Gordon and Betty Moore Foundation and the Boeing Company.

Alvaro del Campo

It rained a couple of days before we left Iquitos, but it was dry again on the evening we flew out. After takeoff, the plane headed west, following the twisting, white-beached Nanay River for a while before banking to the south. As the sun went down behind a spectacular display of pink and yellow clouds, I sat watching the forests down below grow dark.

Just before night fell, when there was barely enough light left to distinguish the rivers from the trees, I noticed a tiny light shining in a place where there wasn’t any other sign of human habitation. In that huge canvas of forest and rivers and clouds, the light was so small ­— a flickering yellow pinpoint ­— that I had to watch intently to keep from losing it. I had lost my bearings by then and had no way of knowing whether it was a drilling site, a tourist lodge, a mining operation, a sawmill, an indigenous community, a riverboat, or something else. I watched it for as long as I could, and when it finally faded away I realized that I had been holding my breath.