Showing posts with label EARTH SCIENCES. Show all posts
Showing posts with label EARTH SCIENCES. Show all posts

Wednesday, June 10, 2015

SECRETARY KERRY'S STATEMENT ON 'CLIMATE CHANGE ADAPTATION AND RESILIENCE'

FROM:  U.S. STATE DEPARTMENT
Climate Change Adaptation and Resilience
Press Statement
John Kerry
Secretary of State
Washington, DC
June 9, 2015

Climate change poses a threat to every country on Earth, and we all need to do what we can to take advantage of the small window of opportunity we still have to stave off its worst, most disastrous impacts. But even as we take unprecedented steps to mitigate the climate threat, we also have to ensure our communities are prepared for the impacts we know are headed our way – and the impacts we are already seeing all over the world in the form of heat waves, floods, historic droughts, ocean acidification and more.

Thanks to President Obama’s Climate Action Plan, we’ve taken a number of important steps to increase the resilience of American communities. But as the President has always said, this is a global challenge, and we’re not going to get very far if we keep our efforts contained within our borders. That’s why the United States is deeply committed to helping the rest of the world – especially the poorest and most vulnerable nations – adapt to the changing climate as well.

As part of that commitment, last fall, President Obama announced his intention to create a private-public partnership to provide climate data and information to help promote resilient development worldwide. Today we formally launched the Climate Services for Resilient Development partnership, along with the government of the United Kingdom and our partners at the American Red Cross, the Asian Development Bank, Esri, Google, the Inter-American Development and the Skoll Global Threats Fund. In addition to the $34 million we and our partners are putting toward that new partnership, we also announced a series of individual steps we’re taking to make adapting to climate change easier around the globe – including, for example, the volunteer “climate resilience corps” that the Peace Corps and AmeriCorps will be launching in developing countries, and NASA’s release of the first-ever climate modeling system that breaks data down to the country level, which will enable countries to better target their individual adaptation planning efforts.

In the United States, we’ve developed some of the most advanced technologies and scientific expertise on climate change, and we want to make sure these tools are reaching those who need it the most. Each of the commitments announced today will make it easier for people to take control of their own futures and play an active role in helping to prepare their communities, their countries, and ultimately their planet for the changes ahead.

When it comes to confronting climate change, no country should be forced to go it alone – because no country can possibly address this threat alone. It will require all of us – every country, around the world, doing what it can to contribute to the solution. That understanding is at the core of the initiatives we are unveiling today, it’s what is driving our work toward an ambitious global agreement in Paris later this year, and it’s what will continue to guide our leadership in the fight against climate change in the months and years to come.

Saturday, January 17, 2015

PLANT FOSSILS AND OUR WORLD'S PAST

FROM:  NATIONAL SCIENCE FOUNDATION 

Tiny plant fossils offer window into Earth's landscape millions of years ago
Fossilized plant pieces tell a detailed story of our planet 50 million years ago
Minuscule, fossilized pieces of plants tell a detailed story of what Earth looked like 50 million years ago.

Researchers have discovered a way of determining density of trees, shrubs and bushes in locations over time--based on clues in the cells of plant fossils preserved in rocks and soil.

Tree density directly affects precipitation, erosion, animal behavior and a host of other factors in the natural world. Quantifying vegetation structure throughout time could shed light on how Earth's ecosystems have changed over millions of years.

"Knowing an area's vegetation structure and the arrangement of leaves on the Earth's surface is key to understanding the terrestrial ecosystem," says Regan Dunn, a paleontologist at the University of Washington's Burke Museum of Natural History and Culture. "It's the context in which all land-based organisms live, but we didn't have a way to measure it until now."

The findings are published in this week's issue of the journal Science.

New method offers window into distant past

"The new methodology provides a high-resolution lens for viewing the structure of ecosystems over the deep history of our planet," says Alan Tessier, acting director of the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research along with NSF's Division of Earth Sciences.

"This capability will advance the field of paleoecology and greatly improve our understanding of how future climate change will reshape ecosystems."

The team focused its fieldwork on several sites in Patagonia, which have some of the best preserved fossils in the world.

For years, paleontologists have painstakingly collected fossils from these sites and worked to precisely determine their ages using radiometric dating. The new study builds on this growing body of knowledge.

In Patagonia and other places, scientists have some idea based on records of fossilized pollen and leaves what species of plants were alive at given periods in history.

For example, the team's previous work documented vegetation composition for this area.

But there hasn't been a way to precisely quantify vegetation openness, aside from general speculations of open or bare habitats, as opposed to closed or tree-covered habitats.

"These researchers have developed a new method for reconstructing paleo-vegetation structure in open versus dense forests using plant biosilica, likely to be widely found in the fossil record," says Chris Liu, program director in NSF's Division of Earth Sciences.

"Now we have a tool to look at a lot of important intervals in our history where we don't know what happened to the structure of vegetation," adds Dunn, such as the period just after the mass extinction that killed the dinosaurs.

"Vegetation structure links all aspects of modern ecosystems, from soil moisture to primary productivity to global climate," says paper co-author Caroline Stromberg, a curator of paleobotany at the Burke Museum.

"Using this method, we can finally quantify in detail how Earth's plant and animal communities have responded to climate change over millions of years, vital for forecasting how ecosystems will change under predicted future climate scenarios."

Plant cell patterns change with sun exposure

Work by other scientists has shown that the cells found in a plant's outermost layer, called the epidermis, change in size and shape depending on how much sun it's exposed to while its leaves develop.

For example, the cells of a leaf that grow in deeper shade will be larger and curvier than the cells of leaves that develop in less covered areas.

Dunn and collaborators found that these cell patterns, indicating growth in shade or sun, similarly show up in some plant fossils.

When a plant's leaves fall to the ground and decompose, tiny silica particles inside the plants, called phytoliths, remain as part of the soil layer.

The phytoliths were found to represent epidermal cell shapes and sizes, indicating whether the plant grew in a shady or open area.

The researchers decided to check their hypothesis by testing it in a modern setting: Costa Rica.

Dunn took soil samples from sites in Costa Rica that varied from covered rainforests to open savannas to woody shrublands.

She also took photos looking directly up at the tree canopy (or lack thereof) at each site, noting the total vegetation coverage.

Back in the lab, she extracted the phytoliths from each soil sample and measured them under the microscope.

When compared with tree coverage estimated from the corresponding photos, Dunn and co-authors found that the curves and sizes of the cells directly related to how shady their environment was.

"Leaf area index" and plant cell structures compared

The researchers characterized the amount of shade as "leaf area index," a standard way of measuring vegetation over a specific area.

Testing this relationship between leaf area index and plant cell structures in modern environments allowed the scientists to develop an equation that can be used to predict vegetation openness at any time in the past, provided there are preserved plant fossils.

"Leaf area index is a well-known variable for ecologists, climate scientists and modelers, but no one's ever been able to imagine how you could reconstruct tree coverage in the past--and now we can," says co-author Richard Madden of the University of Chicago.

"We should be able to reconstruct leaf area index by using all kinds of fossil plant preservation, not just phytoliths. Once that is demonstrated, then the places in the world where we can reconstruct this will increase."

When Dunn and co-authors applied their method to 40-million-year-old phytoliths from Patagonia, they found something surprising--vegetation was extremely open, similar to a shrubland today. The appearance of these very open habitats coincided with major changes in fauna.

The paleobiologists plan to test the relationship between vegetation coverage and plant cell structure in other regions around the world.

They also hope to find other types of plant fossils that hold the same information at the cellular level as do phytoliths.

Paper co-authors are Matthew Kohn of Boise State University and Alfredo Carlini of Universidad Nacional de La Plata in Argentina.

In addition to NSF, the research was funded by the Geological Society of America, the University of Washington Biology Department and the Burke Museum.

-NSF-
Media Contacts
Cheryl Dybas, NSF

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