Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Archive for the ‘Warming’ Category

Global temps could rise higher than expected

Posted by feww on December 21, 2009

Global temperatures could rise more than expected, new study shows

The kinds of increases in atmospheric carbon dioxide taking place today could have a significantly larger effect on global temperatures than previously thought, according to a new study led by Yale University geologists. Their findings appear December 20 in the advanced online edition of Nature Geoscience.

The team demonstrated that only a relatively small rise in atmospheric carbon dioxide (CO2) was associated with a period of substantial warming in the mid- and early-Pliocene era, between three to five million years ago, when temperatures were approximately 3 to 4 degrees Celsius warmer than they are today.

Climate sensitivity—the mean global temperature response to a doubling of the concentration of atmospheric CO2—is estimated to be 1.5 to 4.5 degrees Celsius, using current models.

“These models take into account only relatively fast feedbacks, such as changes in atmospheric water vapor and the distribution of sea ice, clouds and aerosols,” said Mark Pagani, associate professor of geology and geophysics at Yale and lead author of the paper. “We wanted to look at Earth-system climate sensitivity, which includes the effects of long-term feedbacks such as change in continental ice-sheets, terrestrial ecosystems and greenhouse gases other than CO2.”

To do this, the team focused on the most recent episode of sustained global warmth with geography similar to today’s. Their reconstructed CO2 concentrations for the past five million years was used to estimate Earth-system climate sensitivity for a fully equilibrated state of the planet, and found that a relatively small rise in CO2 levels was associated with substantial global warming 4.5 million years ago. They also found that the global temperature was 2 to 3 degrees Celsius higher than today while CO2 levels were only between about 365 and 415 parts per million (ppm)—similar to today’s concentration of about 386 ppm.

“This work and other ancient climate reconstructions reveal that Earth’s climate is more sensitive to atmospheric carbon dioxide than is discussed in policy circles,” Pagani said. “Since there is no indication that the future will behave differently than the past, we should expect a couple of degrees of continued warming even if we held CO2 concentrations at the current level.”

0O0

Other authors of the paper include Zhonghui Liu (Yale University and The University of Hong Kong), and Jonathan LaRiviere and Ana Christina Ravelo (University of California, Santa Cruz).

This study used samples provided by the Integrated Ocean Drilling Program and was funded by the National Science Foundation and the Yale Climate and Energy Institute.

Contact: Suzanne Taylor Muzzin
suzanne.taylormuzzin@yale.edu
Yale University

0O0

Global warming likely to be amplified by slow changes to Earth systems

Researchers studying a period of high carbon dioxide levels and warm climate several million years ago have concluded that slow changes such as melting ice sheets amplified the initial warming caused by greenhouse gases.

The study, published in the journal Nature Geoscience, found that a relatively small rise in atmospheric carbon dioxide levels was associated with substantial global warming about 4.5 million years ago during the early Pliocene.

Coauthor Christina Ravelo, professor of ocean sciences at the University of California, Santa Cruz, said the study indicates that the sensitivity of Earth’s temperature to increases in carbon dioxide in the atmosphere is greater than has been expected on the basis of climate models that only include rapid responses.

Carbon dioxide and other greenhouse gases trap heat in the atmosphere, leading to increased atmospheric and sea-surface temperatures. Relatively rapid feedbacks include changes in atmospheric water vapor, clouds, and sea ice. These short-term changes probably set in motion long-term changes in other factors–such as the extent of continental ice sheets, vegetation cover on land, and deep ocean circulation–that lead to additional global warming, Ravelo said.

“The implication is that these slow components of the Earth system, once they have time to change and equilibrate, may amplify the effects of small changes in the greenhouse gas composition of the atmosphere,” she said.

The researchers used sediment cores drilled from the seafloor at six different locations around the world to reconstruct carbon dioxide levels over the past five million years. They found that during the early and middle Pliocene (3 to 5 million years ago), when average global temperatures were at least 2 to 3 degrees Celsius warmer than today, the concentration of carbon dioxide in the atmosphere was similar to today’s levels, about 30 percent higher than preindustrial levels.

“Since there is no indication that the future will behave differently than the past, we should expect a couple of degrees of continued warming even if we held carbon dioxide concentrations at the current level,” said lead author Mark Pagani, an associate professor of geology and geophysics at Yale University.

0O0

Contact: Tim Stephens
stephens@ucsc.edu
831-459-2495
University of California – Santa Cruz

0O0

Related Links:

Posted in Climate Change, CO2, Geophysics, greenhouse gasses, Warming | Tagged: , , , , , | 2 Comments »

Arthur Starts the Hurricane Season

Posted by feww on June 1, 2008

Arthur Forms Punctually Near Belize City, Mexico

Tropical storm Arthur, Atlantic’s first named storm for 2008, lashed Mexico’s Yucatan peninsula with strong winds of about 40 mph (65 kph), dumping heavy rains on Saturday.


Infrared image GOES Floater (updated every hour or so). NOAA – National Hurricane Center

As if with clockwork precision, Arthur was formed just hours before the official June 1 start of the Atlantic hurricane season about 75 miles (125 km) northwest of Belize City, Mexico.

Alma, the tropical storm formed in the Pacific, fizzled out on Friday after sloshing Nicaragua’s Pacific coast, killing three people.

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (purple). The orange circle indicates the current position of the center of the tropical cyclone. The black line and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time. (Graph and caption NOAA)

Related Information:

Related Links:

Posted in air pollution, americas, Climate Change, climate refugees, CO2, CO2e, energy, environment, food, Global Warming, health, More Disasters, politics, Travel, Warming | Tagged: , , , , , , , , , , , , , , | Leave a Comment »

Freshening of deep Antarctic water could prove catasterophic

Posted by feww on April 18, 2008

Scientists have detected changes in salinity of the antarctic water that could drmatically change the ocean currents and the world’s climate.

They found that salty, dense water that sinks near the edge of Antarctica to the bottom of the ocean about 5 km (3 miles) down is becoming fresher and more buoyant.

The Antarctic “bottom water” is responsible for the great ocean conveyor belt, a system of currents that move throughout the Southern, Pacific, Indian and Atlantic Oceans distributing warm water around the globe.

The edge of the remaining part of an ice shelf in the Weddell Sea in Antarctica photo taken on March 4, 2008. REUTERS/Mariano Caravaca/Handout

“The main reason we’re paying attention to this is because it is one of the switches in the climate system and we need to know if we are about to flip that switch or not,” said Rintoul of Australia’s research arm the CSIRO.

“If that freshening trend continues for long enough, eventually the water near Antarctica would be too light, too buoyant to sink and that limb of the global-scale circulation would shut down,” he said earlier today.

the great ocean conveyor belt delivers warm water into the north Atlantic, making Europe warmer than it would otherwise be. The slowing down or stopping of these currents could result in catastrophic changes in the world’s climate.

“We don’t see any evidence yet that the amount of bottom water that’s sinking has declined. But by becoming fresher and less dense it’s moving in the direction of an ultimate shutdown.” Report


The Thermohaline Circulation (THC)

The thermohaline circulation (THC) is the global density-driven circulation of the oceans. Derivation is from thermo- for heat and -haline for salt, which together determine the density of sea water. Wind-driven surface currents (such as the , ) head polewards from the equatorial Atlantic Ocean, cooling all the while and eventually sinking at high latitudes (forming North Atlantic Deep Water). This dense water then flows into the ocean basins. While the bulk of it upwells in the Southern Ocean, the oldest waters (with a transit time of around 1600 years) upwell in the North Pacific (Primeau, 2005). Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth’s ocean a global system. On their journey, the water masses transport both energy (in the form of heat) and matter (solids, dissolved substances and gases) around the globe. As such, the state of the circulation has a large impact on the climate of the Earth.

The thermohaline circulation is sometimes called the ocean conveyor belt, the great ocean conveyer, the global conveyor belt, or, most commonly, the meridional overturning circulation (often abbreviated as MOC). (Source: wikipedia)

Posted in energy, environment, government, politics, Warming | Tagged: , , , , , | Leave a Comment »