Jul 26

Polar ice reveals new secrets of Earth’s climate

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A team of scientists have used air bubbles in polar ice from pre-industrial times to measure the sensitivity of the Earth’s land biosphere to changes in temperature.

The paper published today in Nature Geoscience has verified and quantified the relationship for the first time and shown how it impacts the cycles of carbon between land, ocean and the atmosphere.

About half of the carbon dioxide (CO2) emitted by human activities since 1850 has been taken out of the atmosphere by the land biosphere and the ocean.

How these sinks will behave in the future has been a significant source of uncertainty in climate projections.

The paper led by Dr Mauro Rubino of CSIRO and the Seconda Universita di Napoli has revealed that the Earth’s land biosphere takes up less carbon in a warmer climate.

“Until now it has only been assumed that as the Earth’s surface warms the ability of land-based plants to store carbon is reduced,” paper co-author and CSIRO senior scientist Dr David Etheridge said.

“In this study we were able to quantify the relationship.

“Reduced storage of carbon by the biosphere leads to higher atmospheric CO2.

“This increases the Earth’s surface temperature, which leads to even less carbon stored by the biosphere, causing a positive feedback,” Dr Etheridge said.

The research team measured air trapped in ice core samples from the Australian Antarctic Program’s unique Law Dome site where past atmospheric composition is preserved in fine detail, together with ice cores from the British Antarctic Survey.

“The very high detail preserved in Law Dome ice cores has been a key to unlocking this information,” Dr Mark Curran, co-author from the Australian Antarctic Division said.

The study focused on CO2 changes preserved in ice before, during, and after a naturally-cool period known as the Little Ice Age (1500 to 1750 AD).

This period is well suited to focus specifically on the relationship between CO2 and temperature because it occurred just before the growth of industry and agriculture affected CO2 concentrations and the deposition of pollutants and nutrients.

“Changes in the carbon-13 isotope ratio, which is a signature of carbon from land plants, show that the CO2 changes during the Little Ice Age originated from the land biosphere,” Dr Etheridge said.

Previously published measurements of another natural ice-based tracer of the carbon cycle, a gas called carbonyl sulfide (COS), were used to rule out the possibility that early land-use changes could have contributed to the CO2 change seen through the study period.

This confirmed that the CO2 changes can be related to variations in land surface temperature, which are known from paleoclimate proxies such as tree rings.

The study shows that for every degree celsius of global temperature rise, the equivalent of 20 parts per million less CO2 is stored by the land biosphere.

“How plants and soils respond to warming is one of the big unknowns in climate projections so it’s great for modellers to have some independent numbers to compare against rather than just comparing models with each other,” paper co-author Dr Peter Rayner from the University of Melbourne said.

Dr Etheridge explains that this result is relevant to coming decades, because it shows how the biosphere responds to temperature changes that are comparable in magnitude and duration to the likely future warming.

Previous ecosystem carbon cycle and climate studies have had limited geographical extent and duration.

“This finding, and feedback quantification, will need to be taken into account for models of the Earth system to project future climates under various scenarios of human greenhouse gas emissions, such as the Australian Community Climate and Earth System Simulator (ACCESS),” Dr Etheridge said.

The paper is a result of a collaboration between CSIRO, the Seconda Universita di Napoli, University of Melbourne, British Antarctic Survey, University of East Anglia, Australian Antarctic Division, University of Tasmania and the Australian Nuclear Science and Technology Organisation.

Jul 24

EASTERN & CENTRAL PACIFIC *Full Update* Watching 3 Pacific Tropical Cyclones: Darby, Frank and Georgette

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Tropical Storm Darby has generated Tropical Storm Warnings in Hawaii today, while Tropical Storm Frank is generating ocean swells along the coast of Baja California. Meanwhile Hurricane Georgette is over open waters.

NOAA’s GOES-West satellite captured infrared imagery of all three storms on Sunday, July 24, 2016 at 1200 UTC (8 a.m. EDT). Those images were put together at NASA/NOAA GOES Project office at NASA’s Goddard Space Flight Center in Greebelt, Maryland. NOAA manages the GOES satellites and NASA/NOAA GOES Project uses the data to create images and animations.

Darby Triggers Hawaii Warnings
Today, July 24, 2016, a Tropical Storm Warning is in effect for all islands in the state of Hawaii, except the Big Island. A Tropical Storm Watch is in effect for the Papahanaumokuakea Marine National Monument…from Nihoa Island to French Frigate Shoals.

At 500 AM HST (1500 UTC), the center of Tropical Storm Darby was located near latitude 19.8 North, longitude 157.3 West. Darby is moving toward the west-northwest near 9 mph (15 km/h) and this general motion is expected to continue over the next 48 hours. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Little change in strength is forecast through Monday, with slow weakening Monday night.

What Hawaii Can Expect from Darby
NOAA’s Central Pacific Hurricane Center said today that tropical Storm force winds are expected over parts of Maui County and Oahu through tonight, and over Kauai late tonight and Monday. Swells generated by Darby are impacting the Hawaiian Islands, and will continue through tonight before diminishing on Monday. Storm total rainfall of 6 to 10 inches, with isolated amounts of up to 15 inches. These rains could produce life-threatening flash floods and landslides.

Tropical Storm Frank Holding Steady, But Causing Swells in Baja California
At 11 a.m. EDT (1500 UTC) on Sunday, July 24, 2016, the center of Tropical Storm Frank was located near latitude 20.3 North, longitude 112.4 West. Frank is moving toward the west-northwest near 7 mph (11 kph). A generally west-northwestward motion is expected for the next day or so, followed by a turn toward the west. Maximum sustained winds remain near 65 mph (100 km/h) with higher gusts. Some slow weakening is forecast to begin late Monday.

Swells associated with Frank are affecting the coasts of the southern Baja California peninsula and the state of Sinaloa. These swells could cause life-threatening surf and rip currents.

Hurricane Georgette Strengthening
At 800 AM PDT (1500 UTC), the center of Hurricane Georgette was located near latitude 15.1 North, longitude 124.6 West. That’s about 1,100 miles (1,770km) west-southwest of the southern tip of baja California, Mexico.

Georgette is moving toward the west-northwest near 10 mph (17 km/h), and this motion is expected to continue today. A turn toward the northwest and a decrease in forward speed is forecast tonight. Maximum sustained winds have increased to near 85 mph (140 km/h) with higher gusts. Some additional strengthening is possible today, with slow weakening forecast to begin on Monday.

Jul 22

A Tropical Storm Warning has been issued for the Big Island of Hawaii

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A Tropical Storm Warning has been issued for the Big Island of Hawaii. A Tropical Storm Watch continues for Maui County, including the islands of Maui, Molokai, Lanai and Kahoolawe. Tropical-storm-force winds are expected over the Big Island and are possible over portions of Maui county on Saturday. Tropical Storm Darby is centered about 460 miles (740 km) east of Hilo. Maximum sustained winds are near 65 mph (100 km/h). Little change in strength through Saturday evening is expected.

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Swells generated by Darby are expected to impact the Hawaiian Islands over the next couple of days, possibly becoming damaging along some coastlines Friday and Saturday. Heavy rains are expected to reach the Big Island and portions of Maui county late Friday, potentially impacting the remainder of the state Saturday. These rains could cause life-threatening flash floods as well as rock and mud slides.

Get the latest on this tropical storm by visiting the website of NOAA’s Central Pacific Hurricane Center (CPHC) at

http://www.prh.noaa.gov/cphc/tcpages/?storm=Darby