The leaf annals. [Fossil leaves provide clues about ancient carbon dioxide levels]

Journal Article · Sat Aug 28 00:00:00 EDT 1993 · Science News (Washington, D.C.); (United States)

DOI:https://doi.org/10.2307/3977452· OSTI ID:5705115

Monastersky, R

Knowing what ancient variations in the concentration of carbon dioxide, indicative of climatic change, in the earth's atmosphere have occurred, can help scientists predict what lies in store for the next century as pollution drives carbon dioxide levels up. A new technique offers hope for tracing carbon dioxide levels back in time. Paleobotanists report that morphological studies of fossil leaves can offer a clue. Research on vegetation growing in greenhouse has shown that the density of stomata depends on the atmospheric concentration of carbon dioxide, a relationship found also outside the greenhouse. Palobotanists have developed a stomatal index to evaluate ancient leaves, and then have gone further by devising an equation relating stomata indexes to carbon dioxide concentrations of ancient times. This technique suggests that gas levels 10 million years ago averaged around 370 ppm, then dropped to 280 ppm during a cool spell, later rising back to 370 ppm. As with other techniques, this has some critisms, mentioned in the article, but it does add to the information available for evaluating future climatic change.

• OSTI ID: 5705115
• Journal Information: Science News (Washington, D.C.); (United States), Vol. 144:9; ISSN 0036-8423
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
CARBON DIOXIDE
BIOLOGICAL EFFECTS
LEAVES
FOSSILS
STOMATA
PALEOCLIMATOLOGY
RESEARCH PROGRAMS
CLIMATIC CHANGE
DENSITY
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL EFFECTS
INDEXES
POLLUTION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DOCUMENT TYPES
OPENINGS
OXIDES
OXYGEN COMPOUNDS
PALEONTOLOGY
PHYSICAL PROPERTIES
540110*
550800 - Morphology