Fossil boffins say that dense triple-canopy rainforests, home among other things to gigantic one-tonne boa constrictors, flourished millions of years ago in temperatures 3-5°C warmer than those seen today – as hot as some of the more dire global-warming projections.

The new fossil evidence comes from the Cerrejón coal mine in Colombia, previously the location where the remains of the gigantic 40-foot Titanoboa cerrejonensis were discovered. The snake’s discoverers attracted flak from global-warming worriers at the time for saying that the cold-blooded creature would only have been able to survive in jungles a good bit hotter than Colombia’s now are.

But now, according to further diggings, there is more evidence to support the idea that a proper rainforest similar to those now seen in the tropics existed at the time of the Titanoboa – despite the much hotter temperatures. This could be seen as conflicting with the idea that a rise of more than two or three degrees would kill off today’s jungles with devastating consequences for the global ecosystem of which we are all part.

“Rainforests, with their palms and spectacular flowering-plant diversity, seem to have come into existence in the Paleocene epoch, shortly after the extinction of the dinosaurs 65 million years ago,” says Carlos Jaramillo of the Smithsonian Tropical Research Institute. “Forests before the mass extinction were quite different from our fossil rainforest at Cerrejón. We find new plant families, large, smooth-margined leaves and a three-tiered structure of forest floor, understory shrubs and high canopy.”

Jaramillo and other boffins from the parent Smithsonian Institution in the US probed fossilised leaf remains and identified the plant families Araceae, Arecaceae, Fabaceae, Lauraceae, Malvaceae and Menispermaceae – which are apparently “still among the most common neotropical rainforest families”.

The scientists say that leaf fossil evidence and the very size of the Titanoboa indicate that the jungles of the Paleocene saw temperatures of 30-32°C, as opposed to the 27°C common in the Colombian rainforest today.

A common goal of global-warming reduction efforts is to limit temperature rises to 2 degrees, though some say this is unachievable and a rise of at least 4 degrees is inevitable. The well-known Intergovernmental Panel on Climate Change (IPCC) report of 2007 predicted a rise of 3 degrees by 2100.

The new research could mean that – assuming the warming arrives on schedule – that the world’s jungles will not turn to desert as is sometimes expected. Rather, a picture more like that of 65 million years ago might emerge.

“We’re going to have a novel climate where it is very hot and very wet. How tropical forest species will respond to this novel climate, we don’t know,” senior Smithsonian boffin S Joseph Wright told the IPCC at the time.

Fortunately nobody seems to be suggesting that global warming will see the return of enormous 40-foot constrictors. Even the humdrum modern snakes of today’s rainforest occasionally perform gut-busting feats such as scoffing entire jaguars, so Titanoboa would presumably have regarded a human being as merely a light snack.

It’s possible that the lush superwarm jungles of the globally-warmed future might be a bit less diverse than today’s, however, as it seems that the old-time ones were.

“We were very surprised by the low plant diversity of this rainforest. Either we are looking at a new type of plant community that still hadn’t had time to diversify, or this forest was still recovering from the events that caused the mass extinction 65 million years ago,” says Scott Wing, another Smithsonian scientist involved in the studies.

The scientists say their latest research will be published in the Proceedings of the National Academy of Sciences journal shortly. ®

Conservation pioneer Russell A. Mittermeier started this year’s Roger Tory Peterson Memorial Lecture (April 5) with a quiz. In front of several hundred listeners at Harvard’s Science Center he turned on a small recorder.

The sudden call of an animal — piercing and reedy — shot like an alarm across the expanse of Lecture Hall B.

Mittermeier, president of the biodiversity protection group Conservation International, asked: What is it?

From some of the hundreds there came shouted answers. A whale? A river otter? But few got the right answer: the eerie forest voice of the indri.

The indri is the largest species of lemur, a kind of primate found only on Madagascar, a lushly biodiverse island off the southeast coast of Africa.

This lean, saucer-eared black-and-white primate is “symbolic of the challenge” confronting humankind, said Mittermeier: a period of catastrophic extinction that could strip the world of 30 percent of its plant and animal species by the end of this century. Among primates alone, he said, one in three is at risk.

Biodiversity, even in just the “ecological services” it provides, like pollination, underpins the well-being of humankind, he said. Yet despite the extinction challenge, humans at large remain largely ignorant, said Mittermeier, “and our ignorance extends to our largest living relatives, non-human primates.”

Lemurs — some weighing just 30 grams — are related to the evolutionary branch that produced humans.

The world’s diversity of plants and animals — about 10 million species, most of them unrecorded — face accelerating pressures of human origin. Those that are regional include mining, invasive species, the pet trade, hunting, and logging.

“Logging of tropical forests is a 19th century activity that has no place in the modern world,” said Mittermeier. His slides included a seeming moonscape on Madagascar — treeless slopes that turn the nation’s rivers red with eroded topsoil.

Hunting for “bush meat” takes its toll too, he said, showing a disturbing image: the severed head of a great ape in a marketplace dish, next to a bunch of bananas. In another image, radiated tortoises were lined belly-up on a Madagascar beach. Their livers are coveted as a tasty pâté.

Other extinction pressures — climate change and deforestation — are global, he said.

But think of climate change as both a threat and an opportunity, said Mittermeier, whose lecture was titled “Conserving the World’s Biodiversity: How the Climate Crisis Could Both Hurt and Help.”

About 20 percent of the carbon emissions altering the atmosphere come from the burning of tropical forests. Putting a halt to this, he said, is the most cost-efficient way to cut down on Earth-warming gases.

Beyond climate change, Mittermeier added three other important conservation concepts: hot spots, “megadiversity” countries, and high-biodiversity wilderness areas.

All biodiversity is important, he said, but the world’s 35 “hot spots” contain a high number of species and face a high level of threat. (Madagascar is one example.)

These resource-dense areas have shrunk to 2.3 percent of the Earth’s land surface, an area about the size of India. But compressed within are 50 percent of the world’s plants and 40 percent of its vertebrates.

“Megadiversity” countries number 18, with Brazil and Indonesia at the top of the list for abundant biodiversity. Contained within are two-thirds of the planet’s terrestrial, freshwater, and marine species.

The world’s high-biodiversity wilderness areas, including the Amazon region of South America, cover 6 percent of Earth’s land surfaces, but remain largely intact.

Taken together, these three geographical areas of biodiversity also contain the world’s biggest share of linguistic and cultural diversity. Spoken there are 74 percent of the Earth’s 6,900 languages.

After seven years of graduate study, Mittermeier left Harvard in 1977 with a Ph.D. in biological anthropology. His dissertation was on the eight primate species known to inhabit Surinam, South America’s smallest sovereign state.

In his decades of fieldwork after that, the polymathic Mittermeier acquired fluency in German, Spanish, Portuguese, French, and Sranan Tongo, a creole language widely used in Surinam.

He also took the time to write 225 scientific and popular articles, along with eight books.

Since 1989, Mittermeier has been president of Conservation International, a Washington, D.C.-area group devoted to protecting global biodiversity and the environmental, economic, and cultural values represented by the natural world.

In 1998, he was named by Time magazine as one of the “EcoHeroes for the Planet.”

It was all that writing and all that fieldwork and all that advocacy on behalf of the Earth’s threatened biodiversity that landed Mittermeier back at Harvard as the 12th recipient of the Roger Tory Peterson Medal. The award is sponsored every year by the Harvard Museum of Natural History.

The medal comes with one obligation — to deliver a lecture in memory of Peterson. He was the American naturalist, artist, and ornithologist (1908-1996) credited with writing the first modern field guide. (“A Field Guide to the Birds” appeared in 1934, and spawned decades of guides to birds, insects, plants, and other living things.)

Previous recipients of the Peterson medal include Jane Goodall, Richard E. Leakey, and Edward O. Wilson, Pellegrino University Professor Emeritus of biology at Harvard — a man Mittermeier called “the Darwin of the 20th century, and the 21st century.”

What will the cities of the future look like?

Harvard’s Graduate School of Design (GSD) offered some ideas last week at a three-day international conference, “Ecological Urbanism: Alternative and Sustainable Cities of the Future,” April 3-5.

The time is right, said organizers. Today, more than half of the world’s 6 billion people live in cities — and by 2050 two-thirds will dwell in energy-intensive urban areas. At the same time, cities face pressures related to health, climate change, air pollution, traffic, and reliable supplies of energy and water.

Designers can help reduce the environmental impact of cities, organizers said. After all, the energy to light, heat, and cool urban buildings accounts for nearly half the globe’s burden of greenhouse gases.

In the United States, a majority of the country — more than 280 million people — live in urban areas. Since 1950, most of the 10 most populated U.S. cities have shifted from the Rust Belt to the Sun Belt — creating centers that, by and large, are less racially and economically diverse than their older counterparts.

Big U.S. cities in general are less racially and economically diverse than they were 50 years ago, said conference presenter Lizabeth Cohen, Harvard’s Howard Mumford Jones Professor of American Studies and chair of the History Department. “Let’s not forget the social dimension of sustainability.”

Or the impact of cities on health. There were lunchtime conference discussions on obesity and mental health in the urban environment.

Or even what activist art can do in cities. John Bela, a director of the San Francisco design and art collective Rebar, described one project: an annual Park(ing) Day that turned a few square feet of a public parking space into a patch of green, rest, and shade that could be leased for 5 cents a minute.

If future cities are going to work, designers will have a hand in it, said Harvard President Drew Faust, who addressed the assembled experts Saturday (April 4).

“There is an invitation here to turn crisis into opportunity,” she said. “You here in this room have been given the mantle of the future.”

Visions of that future could be seen between sessions in a winding, colorful exhibit on display through May 17 in Gund Hall.

There were small-scale marvels, including energy harvesting textiles, electric cars that stack like shopping carts, and fritted glass that shimmers like beads to let in light and temper heat.

There were grand, wistful visions of the future, too. In a mural of “vegetal cities,” bicycles wheeled along grassy roadways under trellis-like wooden bridges and in the shade of buildings roofed with vegetation. Imagined “archiborescent cities” rose wave-like at seaside, nestled in desert canyons, and limned a forest with tree houses.

The conference sessions in Piper Auditorium, crowded with nearly 500 registrants from across the world, had a harder edge.

As modern cities grow up and out, what sustainable systems will deliver food, energy, and water? How will cities deal with noise, light, and odor? To reduce the urban carbon footprint, how should new buildings be built and old ones fixed?

First, grasp the big picture of Earth’s fragile and limited resources, said Mahadev Raman during a Sunday (April 5) session on engineering ecology. He’s an engineer with the global design firm Arup and teaches sustainable design at Princeton University.

An imaginary globe filled with the Earth’s water would barely cover Europe, he showed on a slide of the world map. A similar globe filled with the planet’s entire atmosphere is even smaller. “Our ability to pollute is quite significant,” said Raman.

A small dot on the same slide represented all of Earth’s fossil fuels. “That’s the tiny thing we’re all fighting for,” he said — and a third of it is already gone.

Meanwhile, buildings alone give off the lion’s share of global-warming pollutants, said Raman, using U.K. cities as an example of the developing world’s energy appetite. But he pointed to “the hope in this story”: In a world that now uses 15 terawatts of energy a year — that is, 15 trillion watts — renewable sources promise much more.

The potential energy from wind is 370 terawatts a year, said Raman, and from solar is an astonishing 89,000 terawatts annually. “There’s plenty of renewable energy around,” he said. “There is a ‘there’ there.”

But the potential of renewables can only be realized by finding what has been missing so far, said Raman: “the willingness to invest.”

Cities can save energy, too, with loop-like “industrial symbiosis” — regional systems of sharing excess materials and energy. University of Toronto landscape researcher Pierre Bélanger, who will join the GSD faculty in July, outlined the example of Kalundborg, Denmark. Garbage is burned for energy, he said, and waste streams from industry are “repatriated” for other uses.

Another example of the hope and potential in the built environment ran like a thread through the three-day conference: Masdar, a $22 billion planned city near Abu Dhabi in the United Arab Emirates (UAE). It has been designed from scratch to be a solar-powered, low-carbon city of 2.5 square miles of reclaimed desert.

A comprehensive look at Masdar came from someone who has worked on the project: GSD Adjunct Professor of Environmental Technology Matthias Schuler, a managing director of the climate engineering firm Transsolar.

Hot desert winds will be channeled along short, shaded streets and cooled through finger-like parks irrigated with waste water. There are limitations, said Schuler, including the realization that solar power will not be enough to fill the little city’s needs.

“Masdar is an experiment,” said Raman later. “It will teach us a lot” — even though the biggest challenge “is how to make existing cities work.”

Christoph Reinhart, who teaches architectural technology at GSD, said energy-efficient structures can go up “anywhere in the world” — at a price. A 50 percent reduction in energy use (compared to a conventional building) would require a premium of as much as 15 percent; an 80 percent reduction might cost a builder up to 30 percent more.

But any efficiency gains depend on occupant behavior, said Schuler. The way occupants act can more than double the energy a building saves, or double the energy it uses.

“We’ve gotten into some very bad habits in terms of consumption,” observed Raman. “Future generations are going to have to do more with less.”

Scientists at Harvard University have found that tropical cyclones readily inject ice far into the stratosphere, possibly feeding global warming.

The finding, published in Geophysical Research Letters, provides more evidence of the intertwining of severe weather and global warming by demonstrating a mechanism by which storms could drive climate change. Many scientists now believe that global warming, in turn, is likely to increase the severity of tropical cyclones.

“Since water vapor is an important greenhouse gas, an increase of water vapor in the stratosphere would warm the Earth’s surface,” says David M. Romps, a research associate in Harvard’s Department of Earth and Planetary Sciences. “Our finding that tropical cyclones are responsible for many of the clouds in the stratosphere opens up the possibility that these storms could affect global climate, in addition to the oft-mentioned possibility of climate change affecting the frequency and intensity of tropical cyclones.”

Romps and co-author Zhiming Kuang, assistant professor of climate science in Harvard’s Faculty of Arts and Sciences, were intrigued by earlier data suggesting that the amount of water vapor in the stratosphere has grown by roughly 50 percent over the past 50 years. Scientists are currently unsure why this increase has occurred; the Harvard researchers sought to examine the possibility that tropical cyclones might have contributed by sending a large fraction of their clouds into the stratosphere.

Using infrared satellite data gathered from 1983 to 2006, Romps and Kuang analyzed towering cloud tops associated with thousands of tropical cyclones, many of them near the Philippines, Mexico, and Central America. Their analysis demonstrated that in a cyclone, narrow plumes of miles-tall storm clouds can rise so explosively through the atmosphere that they often push into the stratosphere.

Romps and Kuang found that tropical cyclones are twice as likely as other storms to punch into the normally cloud-free stratosphere, and four times as likely to inject ice deep into the stratosphere.

“It is … widely believed that global warming will lead to changes in the frequency and intensity of tropical cyclones,” Romps and Kuang write in Geophysical Research Letters. “Therefore, the results presented here establish the possibility for a feedback between tropical cyclones and global climate.”

Typically, very little water is allowed passage through the stratosphere’s lower boundary, known as the tropopause. Located some 6 to 11 miles above the Earth’s surface, the tropopause is the coldest part of the Earth’s atmosphere, making it a barrier to the lifting of water vapor into the stratosphere: As air passes slowly through the tropopause, it gets so cold that most of its water vapor freezes out and falls away.

But if very deep clouds, such as those in a tropical cyclone that can rise through the atmosphere at speeds of up to 40 miles per hour, can punch through the tropopause too quickly for this to happen, they can deposit their ice in the warmer overlying stratosphere, where it then evaporates.

“This suggests that tropical cyclones could play an important role in setting the humidity of the stratosphere,” Romps and Kuang write.

Romps and Kuang’s research was funded by the Eppley Foundation and NASA.