NASA Lidar Lasers to Map Earth's Forests in 3D

An artist's conception of the 3D maps of forest architecture that data from GEDI could produce.

Credit: NASA's Goddard Space Flight Center

A new laser instrument developed for the International Space Station is expected to generate incredible 3D maps of Earth's forests.

The instrument called Global Ecosystem Dynamics Investigation (GEDI) uses lidar, a special kind of laser technology, to create detailed 3D maps and measure the biomass of forests.

NASA has already launched a satellite designed to measure carbon dioxide in the atmosphere, but the new instrument, once launched, will allow scientists to estimate the total amount of carbon stored here on Earth inside trees.

"(GEDI) lidar will have a tremendous impact on our ability to monitor forest degradation, adding to the critical data needed to mitigate the effects of climate change," Patrick O'Shea, chief research officer at the University of Maryland, said in a statement.

Scientists already knew that trees absorb carbon. What scientists don't know is how much they store.

This is a problem because scientists can't predict how much extra carbon would escape into the atmosphere if a forest was destroyed or if planting new trees would be enough to offset the emissions.

"One of the most poorly quantified components of the carbon cycle is the net balance between forest disturbance and regrowth," Ralph Dubayah, the (GEDI) principal investigator at the University of Maryland, said in the same statement.

GEDI's lidar instrument works by shooting streams of light particles at the Earth that then reflect back and are picked up by a detector.

The time it takes the particles to reach Earth and bounce back is converted into a distance.

Every material that the light particles pass through on their journey leaves behind a "fingerprint" that the detector can read.

That means that light particles that pass through leafy tree canopies will look different than the particles that pass through branches or trunks. The unique markers will allow scientists to construct detailed 3D maps of forest architecture.

The lidar pulses will measure the height of trees to about a 3-foot (1 meter) accuracy and allow scientists to estimate the total biomass in a forest and how much carbon it's storing.

GEDI will have three lasers that will shoot out a total of 14 laser beams that will cover about 4 miles (6.5 kilometers). The team of engineers behind GEDI estimate that it will send out about 16 billion laser pulses every year.

Piers Sellers, deputy director of Goddard's Sciences and Exploration Directorate, said GEDI's data will be invaluable when it's combined with historic records of carbon levels collected by satellites like Landsat and MODIS which have been hovering over Earth for decades.

Scientists will also combine the 3D maps with images, maps and data collected from other satellites.

The ultimate goal is to create a database that will monitor changes in forests over time.

Scientists hope the combined data will reveal more about land use, biodiversity and climate change effects.

NASA officials estimate that engineers will complete GEDI by 2018. Once aboard the space station, it will scan most tropical and temperate forests between 50 degrees north and 50 degrees south latitude.

Climate Change Caused by the Ocean Circulation and Atmosphere

The Thermohaline Circulation or ocean conveyor belt moves heat and water between the hemispheres, along the ocean bottom. It also moves carbon dioxide.

Most of the concerns about climate change have focused on the amount of greenhouse gases that have been released into the atmosphere, but in a new study published in Science, a group of Rutgers researchers have found that circulation of the ocean plays an equally important role in regulating the earth's climate.

In their study, the researchers say the major cooling of Earth and continental ice build-up in the Northern Hemisphere 2.7 million years ago coincided with a shift in the circulation of the ocean - which pulls in heat and carbon dioxide in the Atlantic and moves them through the deep ocean from north to south until it's released in the Pacific.

The ocean conveyor system, Rutgers scientists believe, changed at the same time as a major expansion in the volume of the glaciers in the northern hemisphere as well as a substantial fall in sea levels.

It was the Antarctic ice, they argue, that cut off heat exchange at the ocean's surface and forced it into deep water. They believe this caused global climate change at that time, not carbon dioxide in the atmosphere.

"We argue that it was the establishment of the modern deep ocean circulation - the ocean conveyor - about 2.7 million years ago, and not a major change in carbon dioxide concentration in the atmosphere that triggered an expansion of the ice sheets in the northern hemisphere," says Stella Woodard, lead author and a post-doctoral researcher in the Department of Marine and Coastal Sciences.

Their findings, based on ocean sediment core samples between 2.5 million to 3.3 million years old, provide scientists with a deeper understanding of the mechanisms of climate change today.

The study shows that changes in heat distribution between the ocean basins is important for understanding future climate change.

However, scientists can't predict precisely what effect the carbon dioxide currently being pulled into the ocean from the atmosphere will have on climate.

Still, they argue that since more carbon dioxide has been released in the past 200 years than any recent period in geological history, interactions between carbon dioxide, temperature changes and precipitation, and ocean circulation will result in profound changes.

Scientists believe that the different pattern of deep ocean circulation was responsible for the elevated temperatures 3 million years ago when the carbon dioxide level in the atmosphere was arguably what it is now and the temperature was 4 degree Fahrenheit higher.

They say the formation of the ocean conveyor cooled the earth and created the climate we live in now.

"Our study suggests that changes in the storage of heat in the deep ocean could be as important to climate change as other hypotheses, tectonic activity or a drop in the carbon dioxide level, and likely led to one of the major climate transitions of the past 30 million years," says Yair Rosenthal, co-author and professor of marine and coastal sciences at Rutgers

ESA Releases Bad and Good News from Earth's Atmosphere Studies

Carbon dioxide emissions increased in East Asia (right) at an average rate of 9.8% per year from 2003 to 2011, but nitrogen oxides increased by ‘only’ 5.8% per year.  

This indicates a use of cleaner technology in East Asia. 

North America and Europe, however, show slightly decreasing trends for both gases. 

The maps show the corresponding spatial pattern as obtained from the satellite data: red corresponds to regions with high values of NOx and CO2, while blue indicates background values.

Credit: ESA

While Europe and North America show a decrease in emission trends between 2003 and 2011, emissions related to economic growth in East Asia continue to rise, but with a reduction in nitrogen oxides emitted per amount of carbon dioxide.

This demonstrates the use of cleaner technology in East Asia.

Nitrogen oxides are generated during the high-temperature combustion of fossil fuels in automobiles and industrial machinery.

They contribute significantly to a reduction of air quality and can be the cause of respiratory problems.

At the same time, these sources release large amounts of carbon dioxide. Carbon dioxide is toxic only at very high concentrations, but is the most important man-made greenhouse gas, leading to global warming and its related consequences.

In a study published yesterday in Nature Geoscience, scientists from the University of Bremen in Germany used data from the Sciamachy instrument on ESA’s Envisat satellite to measure nitrogen dioxide and carbon dioxide trends from 2003 to 2011.

They also exploited  Sciamachy-based data products generated within the ‘GHG-CCI’ project under ESA’s Climate Change Initiative.

“Nitrogen dioxide has a relatively short lifetime, hours, compared to carbon dioxide, which lasts decades, and is a suitable tracer of recently emitted carbon dioxide from fossil fuel combustion,” explained Maximilian Reuter, lead author of the study.

“Sciamachy measured nitrogen dioxide and carbon dioxide simultaneously. We used a spatial high-pass filtering method to isolate the anthropogenic carbon dioxide signal from overlaying signals due to uptake and release of carbon dioxide by vegetation.”

Satellite-derived CO2 concentrations proportional to local anthropogenic emissions in North America and Europe. 

The green line shows the mean value and the grey-shaded area its variability and uncertainty. 

This indicates that less CO2 is emitted during weekends compared to week days.

Using this method, the scientists were able to better see where and when carbon dioxide was emitted.

For example, it showed that less carbon dioxide from local anthropogenic sources is emitted during weekends in Europe and North America compared to week days.

“This has never been observed from space before and shows how accurate the used method is,” said Dr Reuter.

Although Envisat’s mission ended in 2012, a decade of data from its 10 instruments is still being exploited for studies on Earth’s atmosphere, land, oceans and ice caps.

“Unfortunately, none of the existing nor any of the planned near-future satellites are designed to directly observe carbon dioxide emissions of cities, power plants, volcanoes or other important emission hot spots,” said Michael Buchwitz, co-author of the study and GHG-CCI scientific leader.

“This will only be possible with the proposed mission CarbonSat.”

CarbonSat is one of the two candidates for ESA’s eighth Earth Explorer satellite.

Using the unique spectroscopic fingerprint of carbon dioxide and methane, CarbonSat aims to image these two strong greenhouse gases at very high resolution.

The mission would lead to a better understanding of the sources and sinks of atmospheric carbon dioxide and methane.

MODIS Witnesses Deforestation in Borneo: Agricultural fires rage

The skies over Indonesian Borneo is filled with the smoke from hundreds of fires set deliberately to clear indigenous forest areas for subsistence farmland and illegal logging. 

A shroud of thick, gray smoke hangs over the area when the Aqua satellite captured this image on Sept. 25, 2014. 

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua satellite detected dozens of fires (locations outlined in red) across the entire region from Central Borneo to South Borneo and even on East Laut Island. 

Credit: Jeff Schmaltz, MODIS Rapid Response Team.

The skies over Indonesian Borneo are filled with the smoke from hundreds of fires set deliberately to clear indigenous forest areas for subsistence farmland and illegal logging.

A shroud of thick, gray smoke hung over the area when the Aqua satellite captured this image on September 25, 2014.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua satellite detected dozens of fires (locations outlined in red) across the entire region from Central Borneo to South Borneo and even on East Laut Island.

Widespread burning in lowland forests on Borneo is an annual, man-made occurrence.

People use fires to manage and create agricultural lands, including large palm tree plantations that supply palm oil for biodiesel fuel; others are set accidentally during illegal exploitation and logging.

Lowland tropical forests are underlain by a swampy layer of peat that can be up to 20 meters (66 feet) thick.

During the rainy season, when the peat is waterlogged, leaves and other organic matter in the soil don't decay; when the peat dries out, it becomes flammable.

Burning peat generates huge amounts of smoke as is evident in this satellite image. These fires contribute significantly to annual greenhouse gas emissions.

In addition, the smoke released by any type of fire (forest, brush, crop, structure, tires, waste or wood burning) is a mixture of particles and chemicals produced by incomplete burning of carbon-containing materials.

All smoke contains carbon monoxide, carbon dioxide and particulate matter (PM or soot).

Smoke can contain many different chemicals, including aldehydes, acid gases, sulphur dioxide, nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, styrene, metals and dioxins.

Human's exposure to adverse air quality and smoke should be limited as it can cause severe respiratory ailments.

NASA, partners target megacities carbon emissions

Artist's concept of the LA Megacities Carbon Project observing system. 

Ground sensors atop towers and buildings measure carbon dioxide, methane and carbon monoxide. 

An instrument atop Mt. Wilson scans the basin multiple times daily. 

Aircraft, mobile laboratories and satellites round out the network. 

Credit: NASA/JPL-Caltech

Driving down busy Interstate 5 in Los Angeles in a nondescript blue Toyota Prius, Riley Duren of NASA's Jet Propulsion Laboratory, Pasadena, California, is a man on a mission as he surveys the vast urban jungle sprawled around him.

In his trunk, a luggage-sized air-sampling instrument sniffs the outside air through a small tube to measure the greenhouse gases carbon dioxide and methane.

While not a very efficient way to study urban emissions, the ground data being collected are helping Duren and his team build confidence in greenhouse gas measurements taken from aircraft and satellites, which can cover large areas more effectively.

At the next exit, Duren pulls over to admire a scene most Angelenos would try to ignore: a large landfill stretched alongside the freeway.

The instrument in the trunk quickly detects a large plume of methane emanating from the landfill.

A NASA aircraft soon appears overhead, carrying a prototype satellite instrument that records high-resolution images of methane that scientists can use to identify gas plumes.

The pilot buzzes the landfill several times to capture images of the invisible gas, then the plane departs and Duren heads off to his next study area.

The instruments in the Prius and airplane are just two of many elements of the Megacities Carbon Project, an international, multi-agency pilot initiative to develop and test ways to monitor greenhouse gas emissions in megacities: metropolitan areas of at least 10 million people.

Cities and their power plants are the largest sources of human-produced greenhouse gas emissions and are the largest human contributors to climate change.

Duren is principal investigator for the LA component of the Megacities Carbon Project.

He hopes to work with international partners to deploy a global urban carbon monitoring system that will eventually allow local policymakers to fully account for the many sources and sinks, or storage sites, of carbon and how they change over time.

Preliminary estimate of annual on-road carbon dioxide emissions in 2010 for the five counties of the LA megacity, based on annual average weekly traffic data and modeled annual carbon dioxide emissions for different road types. 

A close-up view of southern LA County is at lower left. 

Credit: NASA/JPL-Caltech/Arizona State University

Los Angeles and Paris are pilot cities in the initiative. Efforts are underway to add other cities around the world.

When fully established in late 2014, the LA network will consist of 15 monitoring stations around the LA basin.

Most will use commercially available high-precision greenhouse gas analyzers to continuously sample local air.

The LA network encompasses the portions of the South Coast Air Basin that produce the most intense greenhouse gas emissions in California.

Megacities scientists will also periodically take to the road and to the skies to collect mobile measurements of the local atmosphere to better define individual emissions sources and environmental conditions.

Read the full article here

2014 Arctic Sea Ice Minimum Sixth Lowest on Record

Arctic sea ice hit its annual minimum on Sept. 17, 2014. 

The red line in this image shows the 1981-2010 average minimum extent. 

Data provided by the Japan Aerospace Exploration Agency (JAXA) GCOM-W1 satellite.

Image Credit: NASA/Goddard Scientific Visualization Studio

Arctic sea ice coverage continued its below-average trend this year as the ice declined to its annual minimum on Sept. 17, according to the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado, Boulder.

Over the 2014 summer, Arctic sea ice melted back from its maximum extent reached in March to a coverage area of 1.94 million square miles (5.02 million square kilometers), according to analysis from NASA and NSIDC scientists.

This year’s minimum extent is similar to last year’s and below the 1981-2010 average of 2.40 million square miles (6.22 million square km).

"Arctic sea ice coverage in 2014 is the sixth lowest recorded since 1978. The summer started off relatively cool, and lacked the big storms or persistent winds that can break up ice and increase melting," said Walter Meier, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“Even with a relatively cool year, the ice is so much thinner than it used to be,” Meier said. “It’s more susceptible to melting.”

This summer, the Northwest Passage above Canada and Alaska remained ice-bound.

A finger of open water stretched north of Siberia in the Laptev Sea, reaching beyond 85 degrees north, which is the farthest north open ocean has reached since the late 1970s, according to Meier.


An animation of daily Arctic sea ice extent from March 21 to Sept. 17, when the ice appeared to reach it’s minimum extent for the year. 

It’s the sixth lowest minimum sea ice extent in the satellite era. The data was provided by the Japan Aerospace Exploration Agency (JAXA) GCOM-W1 satellite.

Image Credit: NASA/GSFC Scientific Visualization Studio/T. Schindler

While summer sea ice has covered more of the Arctic in the last two years than in 2012’s record low summer, this is not an indication that the Arctic is returning to average conditions, Meier said.

This year’s minimum extent remains in line with a downward trend; the Arctic Ocean is losing about 13 percent of its sea ice per decade.

To measure sea ice extent, scientists include areas that are at least 15 percent ice-covered. The NASA-developed computer analysis, which is one of several methods scientists use to calculate extent, is based on data from NASA’s Nimbus 7 satellite, which operated from 1978 to 1987, and the U.S. Department of Defense’s Defense Meteorological Satellite Program, which has provided information since 1987.

Due to global warming, larger and larger areas of sea ice melt in the summer and when sea ice freezes over in the winter it is thinner and more reduced. 

As the Arctic summers are getting warmer we may see an acceleration of global warming, because reduced sea ice in the Arctic will remove less CO2 from the atmosphere, according to Danish scientist Dorte Haubjerg Søgaard, PhD Fellow, Nordic Center for Earth Evolution, University of Southern Denmark and the Greenland Institute of Natural Resources, Nuuk..

In addition to monitoring sea ice from space, NASA is conducting airborne field campaigns to track changes in Arctic sea ice and its impact on climate.

Operation IceBridge flights have been measuring Arctic sea ice and ice sheets for the past several years during the spring.

A new field experiment, the Arctic Radiation – IceBridge Sea and Ice Experiment (ARISE) started this month to explore the relationship between retreating sea ice and the Arctic climate.

Scottish scientists: 'tremendously important' breakthrough in water to hydrogen production process

Chemists in Scotland, at the Cronin laboratory in Glasgow University, have made a major advancement in the process of producing hydrogen from water that may offer cleaner and cheaper gas, and a renewable source of energy.

"The process uses a liquid that allows the hydrogen to be locked up in a liquid-based inorganic fuel," professor Lee Cronin of Glasgow University wrote in the journal Science.

"By using a liquid sponge known as a redox mediator that can soak up electrons and acid we've been able to create a system where hydrogen can be produced in a separate chamber without any additional energy input after the electrolysis of water takes place."

Cronin says the redox mediator allows hydrogen to be produced at 30 times the rate of current processes without requiring more energy.

The new process uses energy from the sun and wind, which, due to lower power outputs, produces significantly less hydrogen.

"Around 95 percent of the world's hydrogen supply is currently obtained from fossil fuels, a finite resource which we know harms the environment and speeds climate change," Cronin's report says.

"The potential for reliable hydrogen production from renewable sources is huge. The sun, for example, provides more energy in a single hour of sunlight than the entire world's population uses in a year."

"If we can tap and store even a fraction of that in the coming years and decrease our reliance on fossil fuels it will be a tremendously important step to slowing climate change."

There is also an ongoing need for Hydrogen extraction from water, coming from the world's space agencies (NASA, ESA, etc) to allow them to occupy, inhabit and produce renewable energy on Mars and other suitable exoplanets outside our Solar System.

Prof Lee Cronin is one of 10 the UK’s most inspirational scientists and engineers named as RISE Leaders for 2014 by the Engineering and Physical Sciences Research Council (EPSRC).

Their contribution to science covers a broad range of disciplines and highlights the diversity and impact of the engineering and physical sciences.

More Information
'Decoupled catalytic hydrogen evolution from a molecular metal oxide redox mediator in water splitting' - Authors: Benjamin Rausch, Mark D. Symes, Greig Chisholm, Leroy Cronin - Science 12 September 2014: Vol. 345 no. 6202 pp. 1326-1330 DOI: 10.1126/science.1257443

Global Warming, Climate Change and solar activity

The number of sunspots (white area here) varies in multi-year cycles. 

As a result, solar irradiance, which influences the Earth's climate, also fluctuates. 

The photo shows a UV image of the sun. 

Credit Image: Trace Project / NASA

The number of sunspots (white area here) varies in multi-year cycles. 

As a result, solar irradiance, which influences the Earth's climate, also fluctuates. The photo shows a UV image of the sun. 

Credit: Trace Project / NASA

The average temperature on Earth has barely risen over the past 16 years. ETH researchers have now found out why, and they believe that global warming is likely to continue again soon.

Global warming is currently taking a break: whereas global temperatures rose drastically into the late 1990s, the global average temperature has risen only slightly since 1998, surprising, considering scientific climate models predicted considerable warming due to rising greenhouse gas emissions.

Climate sceptics used this apparent contradiction to question climate change per se, or at least the harm potential caused by greenhouse gases, as well as the validity of the climate models.

Meanwhile, the majority of climate researchers continued to emphasise that the short-term 'warming hiatus' could largely be explained on the basis of current scientific understanding and did not contradict longer term warming.

Researchers have been looking into the possible causes of the warming hiatus over the past few years. For the first time, Reto Knutti, Professor of Climate Physics at ETH Zurich, has systematically examined all current hypotheses together with a colleague.

In a study published in the latest issue of the journal Nature Geoscience, the researchers conclude that two important factors are equally responsible for the hiatus.

El Niño warmed the Earth
One of the important reasons is natural climate fluctuations, of which the weather phenomena El Niño and La Niña in the Pacific are the most important and well known.

"1998 was a strong El Niño year, which is why it was so warm that year," says Knutti. In contrast, the counter-phenomenon La Niña has made the past few years cooler than they would otherwise have been.

Although climate models generally take such fluctuations into account, it is impossible to predict the year in which these phenomena will emerge, says the climate physicist.

To clarify, he uses the stock market as an analogy: "When pension funds invest the pension capital in shares, they expect to generate a profit in the long term."

At the same time, they are aware that their investments are exposed to price fluctuations and that performance can also be negative in the short term.

However, what finance specialists and climate scientists and their models are not able to predict is when exactly a short-term economic downturn or a La Niña year will occur.

Longer solar cycles
According to the study, the second important reason for the warming hiatus is that solar irradiance has been weaker than predicted in the past few years.

This is because the identified fluctuations in the intensity of solar irradiance are unusual at present: whereas the so-called sunspot cycles each lasted eleven years in the past, for unknown reasons the last period of weak solar irradiance lasted 13 years.

Furthermore, several volcanic eruptions, such as Eyjafjallajökull in Iceland in 2010, have increased the concentration of floating particles (aerosol) in the atmosphere, which has further weakened the solar irradiance arriving at the Earth's surface.

The scientists drew their conclusions from corrective calculations of climate models. In all climate simulations, they looked for periods in which the El Niño/La Niña patterns corresponded to the measured data from the years 1997 to 2012.

With a combination of over 20 periods found, they were able to arrive at a realistic estimate of the influence of El Niño and La Niña.

They also retroactively applied in the model calculations the actual measured values for solar activity and aerosol concentration in the Earth's atmosphere.

Model calculations corrected in this way match the measured temperature data much more closely.

Incomplete measured data
The discrepancy between the climate models and measured data over the past 16 years cannot solely be attributed to the fact that these models predict too much warming, says Knutti.

The interpretation of the official measured data should also be critically scrutinised. According to Knutti, measured data is likely to be too low, since the global average temperature is only estimated using values obtained from weather stations on the ground, and these do not exist everywhere on Earth.

From satellite data, for example, scientists know that the Arctic region in particular has become warmer over the past years, but because there are no weather stations in that area, there are measurements that show strong upward fluctuations. As a result, the specified average temperature is too low.

Last year, British and Canadian researchers proposed an alternative temperature curve with higher values, in which they incorporated estimated temperatures from satellite data for regions with no weather stations.

If the model data is corrected downwards, as suggested by the ETH researchers, and the measurement data is corrected upwards, as suggested by the British and Canadian researchers, then the model and actual observations are very similar.

Warming to recommence
Despite the warming hiatus, Knutti is convinced there is no reason to doubt either the existing calculations for the climate activity of greenhouse gases or the latest climate models.

"Short-term climate fluctuations can easily be explained. They do not alter the fact that the climate will become considerably warmer in the long term as a result of greenhouse gas emissions," says Knutti.

He believes that global warming will recommence as soon as solar activity, aerosol concentrations in the atmosphere and weather phenomena such as El Niño naturally start returning to the values of previous decades.

More information: Huber M, Knutti R: Natural variability, radiative forcing and climate response in the recent hiatus reconciled. Nature Geoscience, online publication 17 August 2014, DOI: 10.1038/ngeo2228

NASA IceBridge: Snow has thinned on Arctic sea ice

The probe, shaped like a ski pole, includes a basket that stays on top of the snow while the tip of the probe plunges down to the sea ice below. 

Credit: Chris Linder / Univ. of Washington.

From research stations drifting on ice floes to high-tech aircraft radar, scientists have been tracking the depth of snow that accumulates on Arctic sea ice for almost a century.

Now that people are more concerned than ever about what is happening at the poles, research led by the Earth Science dept of University of Washington and NASA IceBridge confirms that snow has thinned significantly in the Arctic, particularly on sea ice in western waters near Alaska.

A new study, accepted for publication in the Journal of Geophysical Research: Oceans, a publication of the American Geophysical Union, combines data collected by ice buoys and NASA aircraft with historic data from ice floes staffed by Soviet scientists from the late 1950s through the early 1990s to track changes over decades.

Historically, Soviets on drifting sea ice used meter sticks and handwritten logs to record snow depth. Today, researchers on the ground use an automated probe similar to a ski pole to verify the accuracy of airborne measurements.

"When you stab it into the ground, the basket move up, and it records the distance between the magnet and the end of the probe," said first author Melinda Webster, a UW graduate student in oceanography.

"You can take a lot of measurements very quickly. It's a pretty big difference from the Soviet field stations."

Webster verified the accuracy of airborne data taken during a March 15, 2012 NASA IceBridge flight over the sea ice near Barrow, Alaska.

The following day Webster followed the same track in minus 30-degree temperatures while stabbing through the snow every two to three steps.

UW graduate student Melinda Webster uses a probe to measure snow depth and verify NASA airborne data. 

She is walking on sea ice near Barrow, Alaska, in March 2012. 

Her backpack holds electronics that power the probe and record the data. 

Credit: Chris Linder / Univ. of Washington

The authors compared data from NASA airborne surveys, collected between 2009 and 2013, with U.S. Army Corps of Engineers buoys frozen into the sea ice, and earlier data from Soviet drifting ice stations in 1937 and from 1954 through 1991.

Results showed that snowpack has thinned from 14 inches to 9 inches (35 cm to 22 cm) in the western Arctic, and from 13 inches to 6 inches (33 cm to 14.5 cm) in the Beaufort and Chukchi seas, west and north of Alaska.

That's a decline in the western Arctic of about a third, and snowpack in the Beaufort and Chukchi seas less than half as thick in spring in recent years compared to the average Soviet-era records for that time of year.

"Knowing exactly the error between the airborne and the ground measurements, we're able to say with confidence, Yes, the snow is decreasing in the Beaufort and Chukchi seas," said co-author Ignatius Rigor, an oceanographer at the UW's Applied Physics Laboratory.

NASA Earth Observation GOES: Hurricane Iselle threatens Hawaii

Hurricane Iselle is pictured in the Eastern Pacific Ocean on August 3, 2014

Hurricane Iselle picked up strength in the open Pacific on Monday as the powerful storm barrelled toward Hawaii, US forecasters said.

The NOAA Miami-based National Hurricane Centre upgraded Iselle, now some 1,245 miles (2,005 kilometers) east of Hilo, Hawaii, to a Category Four storm on the five-level Saffir-Simpson scale.

Earlier Monday, it had been listed as a Category Three storm.

NOAA's GOES-West satellite captured this image of a very active Eastern and Central Pacific, hosting three tropical cyclones (from left to right) Genevieve, Iselle and Julio.

Image Credit: NASA/NOAA GOES Project

NASA and NOAA satellites have been supplying forecasters with data developing tropical cyclones in the Eastern and Central Pacific Ocean and over the last several days. There have been as many as five tropical systems at the same time.

On Monday, August 4, there were three tropical systems stretching from west to east: Tropical Depression Genevieve in the Central Pacific, Hurricane Iselle and Tropical Storm Julio in the Eastern Pacific.

This false-colored image represents infrared data on Tropical Storm Iselle on July 31 at 5:23 p.m. EDT from the AIRS instrument aboard NASA's Aqua satellite.

Image Credit: NASA JPL

Tropical Depression Genevieve Strengthens
On August 4, Tropical Depression Genevieve was located about 930 miles (1,495 km) southwest of Honolulu, Hawaii. Maximum sustained winds were still near 35 mph (55 kph).

Genevieve was moving westward at about 16 mph (26 kph). NOAA's Central Pacific Hurricane Center forecasts gradual strengthening late on August 4 and 5, so Genevieve could once again reach tropical storm status.

To the east of Genevieve lies low pressure area known as System 93C. It is producing disorganized showers and thunderstorms.

System 93C is located about 500 miles south of Hilo, Hawaii. This low pressure area is moving to the west at 15 mph and currently has a near zero percent chance of becoming a tropical depression over the next couple of days.

Under the bright lights of an aging sun

Venus can be seen as a black dot eclipsing the Sun in this image from 2012. 

Venus orbits too close to the Sun to the planet to be habitable for life as we know it. 

Venus experiences a runaway greenhouse and the average surface temperatures are thought to be around 864ºF. 

Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove

Life as we know it on Earth is linked to our star, the Sun, which provides our planet with just the right amount of heat and energy for liquid water to be stable in our lakes, rivers and oceans.

However, as the Sun ages, it is steadily growing brighter and brighter. Eventually, the sunlight that supports life will become too great, and it will bring an end to habitability on our planet.

A Star is Born and Ages
The Sun formed some 4.5 billion years ago when gravitational attraction caused a massive cloud of gas and dust to collapse.

Currently the Sun is stable and has been for billions of years. The bright ball of light in our sky goes about its days generating energy by fusing hydrogen atoms in its core.

As the Sun ages it will enter another stage of stellar evolution where it's atmosphere begins to inflate. This is when the Sun will expand into a red giant star, swallowing planets in the inner Solar System, possibly including the Earth.

As time goes on, the Sun will start shedding its atmosphere and will continue to grow into a massive planetary nebula, which is like a large cloud of gas ejected from the old star.

This is a sort of recycling stage, where elements created by the star are sent back to the interstellar medium, thereby providing new materials for more stars to form.

Next, the old core of the Sun will cool and collapse into a dense but small hunk of mass known as a white dwarf star.

Eventually, it will cool to the point where only a cold, dark husk remains.
Life as we know it is intrinsically tied to the life-cycle of the Sun because we rely on its light for energy. Right now, things are perfect for biology. In the future, this will change dramatically.

As the Sun heats up and expands, life on Earth will become increasingly difficult. Long before the Sun becomes a red giant some 4 or 5 billion years from now, our planet will be rendered uninhabitable.

Dying in a Future Solar System
The fate of the Earth as the Sun grows old is not an old topic. For decades, scientists have studied various scenarios for how an ageing Sun will affect Earth's future habitability. Writers and artists, on the other hand, have explored the idea for centuries.

However, humankind will be gone long before a red giant star fills our skies.

Rather than leading us to a rocky ball of ice, an ageing Sun will instead blast the Earth with ever-increasing heat. Before the Sun expands to a red giant, this increased heat will cause dramatic climatic change on our planet.

The Atmosphere in 3-D
Previous models have predicted that an increase of just 6 percent in the solar constant (a measure of incoming solar electromagnetic radiation) would cause a runaway greenhouse effect on Earth that would render the planet uninhabitable as the oceans boil away to space.

Based on this number, Earth's habitability could come to an end in around 650 million years from now. However, a more recent study has extended the expected lifetime of Earth as a habitable world.

Discover the lifecycle of stars with this activity and handout. 

Many people think the different stages in the life of a star are actually different types of stars, rather than just stages in the life of a single star. 

Credit: NASA/JPL, Astronomical Society of the Pacific

New research shows that the accuracy of previous studies, which were based on 'one-dimensional' models of Earth's climate, could be improved.

"One-dimensional models treat the atmosphere as a single vertical column. This single column is meant as a representative average of all points on the Earth," explains Eric Wolf of the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder.

"While one-dimensional models can treat radiative transfer well (i.e. solar energy and the greenhouse effect), they completely ignore many important aspects such as clouds, dynamics, and the pole to equator gradients of energy which ultimately describe our climate."

Wolf and his colleague Brian Toon, also of UC Boulder, used complex, three-dimensional climate models in order to bring more detail into the picture.

"Three-dimensional models, as we refer to them, are general circulation models of climate. They include a fully, spatially-resolved, rotating planet, with clouds, oceans, sea-ice, weather, etc.," Wolf told Astrobiology Magazine.

"The three-dimensional general circulation model I used has also been used for problems of modern climate. General circulation models are considered the most advanced type of climate models."

The added detail of the 3-D models showed that the Earth could remain habitable for longer than previously expected.

"According to my work, the Earth may remain 'habitable' for at least another 1.5 billion years, when the Sun is approximately 15.5 percent brighter than today," said Wolf. "This is the limit of our current study."

It's important to note that a habitable Earth in terms of astrobiology is not necessarily habitable for human beings.

Read the full article here

New Climate Change study shows Indonesia's disastrous deforestation

This photograph taken on February 24, 2014 during an aerial survey mission by Greenpeace in Central Kalimantan province on Indonesia's Borneo Island, shows cleared trees to make way for a palm oil plantation in a Borneo forest

Satellite images have found that Indonesia's ancient forests, a cradle of biodiversity and a buffer against climate change, have shrunk much faster than thought, scientists said on Sunday.

Between 2000 and 2012, Indonesia lost around 6.02 million hectares (14.4 million acres or 23,250 square miles) of primary forest, an area almost the size of Sri Lanka, they reported.

Primary or ancient forests are distinguished from managed forests, which are plantations of trees grown for timber and pulp.

The researchers found that primary forest loss accelerated during the period under review, reaching an annual 840,000 hectares by 2012, nearly twice the deforestation rate of Brazil, which was 460,000 hectares in the same year.

"Indonesia's forests contain high floral and faunal biodiversity, including 10 percent of the world's plants, 12 percent of the world's mammals, 16 percent of the world's reptile-amphibians and 17 percent of the world's bird species," said the study, published in the journal Nature Climate Change.

"Extensive clearing of Indonesian primary forest cover directly results in habitat loss and associated plant and animal extinctions."

Deforestation is also a blow to the fight against climate change, as ancient trees store more carbon emissions from the atmosphere than new ones do, and for a longer period, thus mitigating global warming.

The research, led by geographer Belinda Margono of the University of Maryland, looked at long-term satellite images.

During 2000-2012, total forest cover in Indonesia retreated by 15.79 million hectares, of which 6.02 million, or 38 percent, was primary forest, the investigation found.

Distinguishing between primary and managed forest is vital in the campaign to preserve biodiversity and combat climate change, the paper said.

"It is critically important to know the context of forest disturbance, whether of a high-biomass natural forest or a short-cycle plantation," it said.

"Similarly, the clearing of natural forest has very different implications on the maintenance of biodiversity richness."

It noted that in 2010, the UN's Food and Agricultural Organisation (FAO) put Indonesia's overall forest loss at 310,000 hectares per year from 2000-2005, and 690,000 hectares annually from 2005-2010.

Indonesia itself, in a report to the UN's Framework Convention on Climate Change (UNFCCC) in 2009, estimated forest loss of 1.1 million hectares annually from 2000-2005.

Margono's study found the biggest losers were lowland and wetland forests in Sumatra and Kalimantan, where trees are typically chopped down by loggers for use in farming.

In other islands or island groups, Papua, Sulawesi, Maluku, Java and Bali and Nusa Tenggara, primary forest cover fell back only slightly or remained stable from 2000-2012.

More information: Nature Climate Change, dx.doi.org/10.1038/nclimate2277

NASA's Orbiting Carbon Observatory (OCO)-2 will measure CO2 in the atmosphere

An artists rendition of NASA's Orbiting Carbon Observatory (OCO-2), which will launch on July 1 and measure atmospheric carbon dioxide 

NASA is preparing a July 1 launch for its first satellite dedicated to measuring atmospheric levels of carbon dioxide, a greenhouse gas that plays a key role in climate change.

CO2 levels have reached their highest point in at least 800,000 years, according to the US space agency.

The Orbiting Carbon Observatory (OCO-2) satellite is very similar to its predecessor, OCO-1, which was destroyed during its launch in February 2009.

The satellite will help provide a more complete and global picture of man-made and naturally occurring CO2 emissions as well as the effects of carbon "sinks," like oceans and forests, which absorb and trap the gas.

"Carbon dioxide in the atmosphere plays a critical role in our planet's energy balance and is a key factor in understanding how our climate is changing," said Michael Freilich, director of NASA's Earth Science Division.

"With the OCO-2 mission, NASA will be contributing an important new source of global observations to the scientific challenge of better understanding our Earth and its future," he added in a statement.

The OCO-2 satellite will be launched on a United Launch Alliance Delta II rocket from Vandenberg Air Force Base in California, aiming for an orbit at 438 miles (705 kilometers) above the Earth's surface.

Earth's magnetic field: Important for climate change at high altitudes

New research, published this week, has provided scientists with greater insight into the climatic changes happening in the upper atmosphere.

Scientists found that changes in the Earth's magnetic field are more relevant for climatic changes in the upper atmosphere (about 100-500 km above the surface) than previously thought.

Understanding the cause of long-term change in this area helps scientists to predict what will happen in the future.

This has key implications for life back on earth.

A good understanding of the long-term behaviour of the upper atmosphere is essential; it affects a lot of satellite-based technology, such as global navigation systems and high-frequency radio communication systems.

Some satellites even operate within the upper atmosphere itself.

The increase in atmospheric CO2 concentration has been thought to be the main cause of climatic changes at these high altitudes.

This study suggests that magnetic field changes that have taken place over the past century are as important.

Both increasing levels of CO2 and changes in the Earth's magnetic field affect the upper atmosphere, including its charged portion, also known as the ionosphere.

Ingrid Cnossen

Dr. Ingrid Cnossen from the British Antarctic Survey used computer simulations to compare the effects of these two factors over the past century.

While CO2 causes heat to be trapped in the lower atmosphere, it actually cools the upper atmosphere.

The simulations show that the increase in CO2 concentration over the past 100 years has caused the upper atmosphere, at around 300 km altitude, to cool by around 8 degrees.

At the same altitude, changes in the Earth's magnetic field caused a similar amount of cooling over parts of North America, but caused a warming over other parts of the world, with the strongest warming, of up to 12 degrees, located over Antarctica.

Dr. Ingrid Cnossen said: "Computer simulations are a very important tool in understanding the causes of climate change at high altitudes.

We still can't explain all of the long-term trends that have been observed, but it helps that we now know how important the magnetic field is."

The new simulations also indicate that rising CO2 levels have caused the densest part of the ionosphere to lower by about 5 km globally.

Changes in the Earth's magnetic field can cause much larger changes, but they are very dependent on location and can be either positive or negative; over the southern Atlantic Ocean a decrease in height of up to 50 km was found, while an increase in height of up to 20 km was found over western Africa.

The findings are published in the Journal of Space Weather and Space Climate.

More Information:  The importance of geomagnetic field changes versus rising CO2 levels for long-term change in the upper atmosphere. I. Cnossen dx.doi.org/10.1051/swsc/2014016

Runaway Glacier melt in West Antarctica Ice

The leading edge of the floating ice tongue of the Pine Island Glacier, Antarctica. 

Credit: M. Wolovick

Reports that a portion of the West Antarctic Ice Sheet (WAIS) has begun to irretrievably collapse, threatening a 4-foot rise in sea levels over the next couple of centuries, surged through the news media last week.

But many are asking if even this dramatic news will alter the policy conversation over what to do about climate change.

West Antarctic Ice Sheet (WAIS)

Glaciers like the ones that were the focus of two new studies move at, well, a glacial pace. Researchers are used to contemplating changes that happen over many thousands of years.

This time, however, we're talking hundreds of years, perhaps—something that can be understood in comparison to recent history, a timescale of several human generations.

In that time, the papers' authors suggest, melting ice could raise sea levels enough to inundate or at least threaten the shorelines where tens of millions of people live.

"The high-resolution records that we're getting and the high-resolution models we're able to make now are sort of moving the questions a little bit closer into human, understandable time frames," said Kirsty Tinto, a researcher from Lamont-Doherty Earth Observatory who has spent a decade studying the Antarctic.

"We're still not saying things are going to happen this year or next year. But it's easier to grasp [a couple of hundred years] than the time scales we're used to looking at."

The authors of two papers published last week looked at a set of glaciers that slide down into the Amundsen Sea from a huge ice sheet in West Antarctica, which researchers for years have suspected may be nearing an "unstable" state that would lead to its collapse.

The West Antarctic Ice Sheet (WAIS) is mostly grounded on land that is below sea level (the much larger ice sheet covering East Antarctica sits mostly on land above sea level).

Advances in radar and other scanning technologies have allowed researchers to build a detailed picture of the topography underlying these glaciers, and to better understand the dynamics of how the ice behaves.

Where the forward, bottom edge of the ice meets the land is called the grounding line. Friction between the ice and the land holds back the glacier, slowing its progress to the ocean.

Beyond that line, however, the ice floats on the sea surface, where it is exposed to warmer ocean water that melts and thins these shelves of ice.

As the ice shelves thin and lose mass, they have less ability to hold back the glacier.

What researchers are finding now is that some of these enormous glaciers have become unhinged from the land – ice has melted back from earlier grounding lines and into deeper basins, losing its anchor on the bottom, exposing more ice to the warmer ocean water and accelerating the melting.

The glaciers studied by Eric Rignot’s research team. 

Red indicates areas where flow speeds have increased over the past 40 years. 

The darker the colour, the greater the increase. 

The increases in flow speeds extend hundreds of miles inland. 

Credit: Eric Rignot.

In their paper published in Geophysical Research Letters, Eric Rignot and colleagues from the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, Calif., described the "rapid retreat" of several major glaciers over the past two decades, including the Pine Island, Thwaites, Haynes, Smith and Kohler glaciers.

"We find no major bed obstacle upstream of the 2011 grounding lines that would prevent further retreat of the grounding lines farther south," they write.

"We conclude that this sector of West Antarctica is undergoing a marine ice sheet instability that will significantly contribute to sea level rise in decades to come."

More information: Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011, E. Rignot, J. Mouginot, M. Morlighem, H. Seroussi, B. Scheuchl, Geophysical Research Letters (2014)

Marine Ice Sheet Collapse Potentially Underway for the Thwaites Glacier Basin, West Antarctica, Ian Joughin, Benjamin E. Smith, Brooke Medley, Science (2014)