New research shows using leaves' characteristics improves accuracy measuring past climates

Apr 18, 2011

A study led by Baylor University geologists shows that a new method that uses different size and shape traits of leaves to reconstruct past climates over the last 120 million years is more accurate than other current methods.

The study appeared in the April issue of the journal and was funded by the National Science Foundation.

"Paleobotanists have long used models based on leaf size and shape to reconstruct ancient climates," said Dr. Daniel Peppe, assistant professor of geology at Baylor, College of Arts and Sciences, who is an expert in paleomagnetism, paleobotany and paleoclimatology. "However most of these models use just a single variable or variables that are not directly linked to climate, which obviously limits the models' predictive power. For that reason, they models often underestimate ancient temperatures."

Baylor geology researchers, along with 26 other co-authors from universities around the world, collected thousands of leaves from many different species of plants from 92 climatically-different and plant-diverse locations on every continent except Africa and Antarctica. Multiple linear regression models for mean and mean annual precipitation were developed and then applied to nine well-studied fossil floras.

The results showed:

  • Leaves in cold climates typically have larger, more numerous teeth, and are more dissected. Leaves in wet climates are larger and have fewer, smaller teeth.
  • Leaf habit (deciduous vs. evergreen), local water availability and phylogenetic history all affect the relationships between climate and leaf size and shape.
  • The researchers' multivariate mean annual temperature and mean annual precipitation models offer strong improvements in accuracy and precision over single variable approaches. For example, the mean annual temperature estimates for most of North American fossil floras were considerably warmer and wetter and in better agreement with independent paleoclimate evidence. This suggests that these new models offer the potential to provide climate estimates that will help scientists better understand ancient climates.
"Our study demonstrates that the inclusion of additional leaf traits that are functionally linked to climate improves paleoclimate reconstructions," Peppe said. "This will help us to better reconstruct past climates and ecosystems, which will allow us to study how ecosystems respond to climate change and variations in climate on local, regional and global scales."

Explore further: NASA satellites calling here you come again, Tropical Storm Dolly

add to favorites email to friend print save as pdf

Related Stories

Ancient leaves help researchers understand future climate

May 06, 2010

Potential climate change caused by rising levels of carbon dioxide might be better understood by examining fossil plant remains from millions of years ago, according to biogeochemists. The types of carbon within the leaves ...

Peruvian stalagmites a new basis for 'Inconvenient truth'?

Apr 29, 2009

Will the Netherlands that is dominated by water succumb to the 'Inconvenient Truth' predicted by Al Gore? Dutch researcher Martin van Breukelen analysed stalagmites from the South American Amazon tributaries in Peru. He used ...

Ancient insects preferred warmer climates

Nov 23, 2010

For millions of years, insects and plants have coevolved—leaf-eaters adapting to the modifications of their hosts and plants changing to protect themselves from herbivory. The abundance and diversity of both insects ...

Recommended for you

Tropical Storm Dolly forms, threatens Mexico

4 hours ago

Tropical Storm Dolly formed off Mexico's northeastern coast on Tuesday and headed toward landfall in Tamaulipas state, threatening to spark floods and mudslides, forecasters said.

Giant garbage patches help redefine ocean boundaries

7 hours ago

The Great Pacific Garbage Patch is an area of environmental concern between Hawaii and California where the ocean surface is marred by scattered pieces of plastic, which outweigh plankton in that part of ...

New satellite maps out Napa Valley earthquake

8 hours ago

Scientists have used a new Earth-observation satellite called Sentinel-1A to map the ground movements caused by the earthquake that shook up California's wine-producing Napa Valley on 24 August 2014.

User comments : 0