Tag Archives: Climate

Is Jupiter Earth’s Friend or Foe?

Jupiter1

Jupiter’s largest moon, Ganymede, ducks behind the red giant once every seven days.

Is Jupiter a friendly planet, Earth’s enemy, or perhaps both? For decades, scientists have talked about how the giant gas planet keeps some asteroids from striking our small world, while others have pointed out that Jupiter’s gravity could send some civilization-shattering asteroids our way.

While that debate goes on, a subtler question arises about how influential Jupiter was in the early Solar System. Jupiter is by far the heavyweight planet in the Solar System, weighing in at 320 Earth masses. Its gravity not only influences small asteroids that go by, but also tugs on other planets in the solar system – including our own.

What if Jupiter had had a more eccentric orbit? Could that have affected the habitability of Earth? A new peer-reviewed study published on preprint site Arxiv, called “The role of Jupiter in driving Earth’s orbital evolution,” examines these questions in more detail. It was presented at the Australian Space Science Conference.

At first blush it appears Jupiter’s position in the solar system could vary greatly without hurting life’s beginnings as we know it, but more studies of how other planets influence Earth’s climate are needed before we can better understand what’s going on, the researchers said. Depending on how Jupiter interacts with Earth in different scenarios, Earth’s orbit could vary dramatically, thereby influencing the amount of sun we receive on the surface. Once we begin to figure out the ranges of habitability in the models, this could help us narrow the search for other habitable planets outside the Solar System that have gas giants nearby.

Life-friendly scenarios

Surveys with NASA’s Kepler space telescope and other observatories reveal one great truth about planets: they tend to form in groups. Most planets outside the solar system are found with companions. We’ve also seen an array of planetary systems, including those where gas giants known as “Hot Jupiters” are close to their parent star.

The search for habitability is often focused on finding rocky planets or moons similar in size to the Earth, and ones orbiting at the right distance from a star to make liquid water possible. However, other factors include the variability of a planet’s orbit, or the tilt of its poles, both of which could be influenced by bigger planets in that planet’s solar system.

Researchers got interested in the effects of nearby planets on life after observing the Moon.

“I started looking at the effects of the moon on Earth’s climate,” said University of London geologist David Waltham, a co-author of the study. “It’s often said the moon stabilizes the Earth’s axis. It’s wrong. It actually nearly destabilizes the axis.”

Certainly, if you suddenly took the Moon away, the Earth’s axis would destabilize. But Waltham said the better question is to ask what would happen if there was a larger moon from the beginning.

“Any initially stable planet will eventually become unstable as its spin slows but, without a moon, this could take tens or hundreds of billions of years,” Waltham said.

“Having a moon increases the rate with which the spin slows so that, in Earth’s case for example, it will only take 6 billion years (from formation) for the Earth’s axis to become unstable.”

In a nutshell, taking the Moon away today is not the same thing as not having a Moon in the first place.  We’ve had 4.5 billion years of lunar-generated spin-deceleration.

From there, Waltham began considering scenarios where moons would not destabilize a planet as quickly. One of them would be if the solar system was precessing, or moving, more slowly. This led him to wonder about the influence of other planets on Earth, a question also preoccupying Jonti Horner, an astronomer and astrobiologist at the University of Southern Queensland, who is affiliated with the Australian Centre for Astrobiology.

Jupiter on the move

The researchers ran models of our Solar System. With each iteration, seven of the eight planets in the solar system are in the same starting conditions in terms of mass, location and orbit. The eighth, Jupiter, kept the same mass but was moved around in various ways.

The researchers used different orbital eccentricities ranging from perfectly circular to orbits that are moderately eccentric, or elliptical, where Jupiter’s closest and furthest distances range 20 percent further than usual. In distance terms, this means Jupiter would rove as much as two astronomical units or Earth-sun distances in its orbit, ranging from 4.2 AU from the Sun to 6.2 AU from the sun.

In addition, the authors moved the entire orbit of Jupiter inwards and outwards (testing what would happen if it had formed closer to the Sun, or further away), and at each new location, again tested a range of orbital eccentricities between circular and moderately eccentric. This meant that, in their most extreme close-in scenario, Jupiter came all the way in to 3.4 AU at perihelion, while in the most extreme distant scenario, it ranged out to over 7.4 AU from the Sun.

Using tens of thousands of permutations, Waltham and Horner stepped forward each simulation through a million years of time, recording Earth’s orbital parameters every 100 years and then charting the results.

“The default assumption is this is something that is important,” Horner said. “There’s a lot of flexibility where Jupiter will be, and you would assume that you’d have a very smooth, very gentle variation in how the Earth’s orbit behaves over time.”

The model showed that most of Jupiter’s locations resulted in little change in Earth’s orbit and tilt, although the effect on Earth’s climate is unclear. Horner said he is working with James Gilmore, a climatologist at University of London, to better understand how changes in the Earth’s tilt or orbit would affect its habitability. Changing the tilt would affect the seasons, while changing the orbit would alter the amount of sun on the surface.

Waltham, meanwhile, says there is a discrepancy between the results in this study and a previous one he had done with analytical equations showing that Jupiter’s position has a striking influence on Earth’s climate. While he believes this study is more accurate, he wants to go back to his earlier work to resolve the difference.

Searching for life beyond Earth

Although this simulation dealt specifically with the Earth-Jupiter relationship, there are implications for worlds that are beyond our Solar System’s reaches, the researchers said. Take solar systems that are comprised of planets orbiting in spaces as small as Mercury’s orbit of the Sun.

“It’s about spacing,” Waltham said. “I think there is a strong implication that compact solar systems are less likely to have planets with stable axes, which makes them less likely to be habitable.”

That said, he warns there are no “absolute rules” about habitability. There could be scenarios where the axis moves too quickly for complex life to keep up, but simple life forms such as bacteria are be able to evolve fast enough to adapt to temperature changes.

Horner, meanwhile, is examining scenarios under which giant planets send giant impactors, such as asteroids, towards inner planets. For Earth, a Jupiter-sized planet is both a good and a bad thing. The gas giant absorbs some impacts from meteorites, but also alters the orbits of small bodies and could send them towards Earth.

He added that the new research underscores how a small change in parameters could change habitability wildly, pointing to the need to look at more solar systems in formation to see under what conditions planets form. Examining new solar systems will be a strength of NASA’s forthcoming James Webb Space Telescope, which is launching into space in 2018.

Horner emphasized that the numerous simulations his team ran on Jupiter’s influence in the solar system shows that where planets end up is often a result of chance as much as physics.

“Every object you add to [a planetary] system adds complexity, and the end result is a result of random chances,” said Horner. “So if you change something very small when the solar system is forming, it’s kind of chaotic.”

This article originally published at Space.com
here

Read more: http://mashable.com/2014/06/01/jupiter-earth-stable-axis-habitability/

Experts discuss extreme weather and climate change reporting at the Media Summit

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Image: Alexander Gerst/ESA/NASA/Associated Press

Climate change is a critical discussion in this day and age, and communicating its intricacies can be a challenge. At the Mashable Media Summit we’ve added a session on telling the stories of climate change in the digital age.

Eventbrite - Mashable Media Summit: Formats of Creativity

The session, titled “Talking About the Weather: Telling Extreme Weather and Climate Change Stories in the Digital Age,” will be led by Mashable’s Senior Climate Reporter Andrew Freedman and will analyze the most effective ways to communicate climate change given the multitude of perspectives on the climate change issue.

Speakers joining this session include:

  • Neil Katz, Editor in Chief/ V.P. of Digital Content, The Weather Channel

  • Bernadette Woods Placky, Meteorologist and Climate Matters Program Director, Climate Central

Other previously announced sessions at Media Summit will include media experts like Pete Cashmore, Mashable‘s founder and CEO; Jill Abramson, Harvard University lecturer; Joanna Coles, editor in chief of Cosmopolitan magazine; and Piper Kerman, author of Orange Is the New Black in conversation with Larry Smith, founder of Smith Magazine.

The Media Summit is a one-day conference analyzing the impact of technology on the media industry, with an emphasis on the evolution of storytelling. Speakers will discuss media trends like the rise of big data and mobile, the impact of global social media campaigns, how to use visual platforms to enhance your story and much more.

For a full list of speakers and agenda, check out the Media Summit website. Ticket prices will increase on Thursday, so make sure to reserve your spot early.

Read more: http://mashable.com/2014/11/25/climate-session-media-summit/

NASA and NOAA Agree: 2014 Was Hottest Year On Record

Though it might be hard to believe right now since the Northern Hemisphere is currently experiencing the coldest part of winter, our average global temperatures are increasing at a worrying rate. NASA and NOAA have analyzed the data independently of one another and yet have arrived at the same conclusion: 2014 is the warmest year on record since 1880. This is the 38th consecutive year with above average surface temperatures. The dataset has been released by NASA’s Goddard Institute for Space Studies (GISS).

“NASA is at the forefront of the scientific investigation of the dynamics of the Earth’s climate on a global scale,” NASA’s John Grunsfeld said in a press release. “The observed long-term warming trend and the ranking of 2014 as the warmest year on record reinforces the importance for NASA to study Earth as a complete system, and particularly to understand the role and impacts of human activity.”

Surface temperatures in 2014 averaged 0.8° C (1.4° F) warmer than 1880. This doesn’t mean that 1880 was a particularly hot year; it’s just where the instrumental record begins. It might not seem like a significant increase, but it can have an incredible impact on the environment. This increase has been largely attributed to carbon dioxide released into the atmosphere due to human activity.

Those living in the Midwest or East Coast of the United States will remember last year’s Polar Vortex, which brought extreme winter weather to hundreds of millions of people. However, other parts of the country experienced record-setting temperatures during the summer, offsetting the cold experienced during the winter.

Overall, the planet has been growing increasingly warmer for several decades. Variations in weather patterns have created slight cooling periods, but looking at the larger picture shows that temperatures are definitely looking up, and not in a good way. In fact, nine out of the 10 warmest years since the record began have happened after 2000. The exception is 1998, due to the intense effects of El Niño. 2014 was not affected by El Niño.

Image credit: NASA, Hansen et al. (2010)

“This is the latest in a series of warm years, in a series of warm decades. While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases,” noted Gavin Schmidt, GISS Director.

Though NASA and NOAA have agreed that 2014 was the warmest year since the Industrial Revolution, they used different methods for data collection. Researchers at GISS combined data from 6,300 weather stations to get land temperatures, while ocean temps were retrieved via ships, buoys, and from the Antarctic. NOAA’s conclusion also came from data collected by ships and buoys, though it made use of satellite and radar data as well.

 

 

Read more: http://www.iflscience.com/environment/nasa-and-noaa-agree-2014-was-hottest-year-record

Scientists Think Rivers Of Liquid Nitrogen Once Flowed On Pluto

There are tropics on Pluto. While this may sound counterintuitive, its climate means that there are warmer parts of the world relative to its colder, arctic regions. As new research presented at the 2016 Lunar and Planetary Science Conferencethis week reveals, this diverse climate means that rivers and lakes of liquid nitrogen are likely to form at the surface.

Even with less than half of New Horizons data, scientists are unravelling more and more secrets about the dwarf planet by the day. The latest comes by way of researchers at NASAwho confirm that Pluto despite being on average 5.9 billion kilometers (3.7 billion miles) away from the Sun has seasons.

The central tropical region of Pluto, from 60 north to 60 south, experiences the Sun passing directly overhead. Its arctic region above 30 north experiences prolonged sunlight in the summer months, whilst the arctic region beneath 30 south is utterly frigid in a simultaneous winter.

Pluto is tipped over on its rotational axis at 120, rather wonky compared to Earths 23 tilt. As a result of this, during a northern arctic summer, the region receiving the most heat is its north pole.

Go home Pluto, youre drunk: The extreme axial tilt of the dwarf planet. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The dwarf planet wobbles and shakes on its axis as it orbits the Sun just like Earth does, meaning that these arctic regions advance and retreat over cycles of hundreds of thousands of years. One region, however, never experiences arctic climates.

This band, between 13 N and 13 S, appears to have been gouged out, in that theres a dark, deep stripe compared to the rest of the planet. The researchers think that the constant warm band here means that ice and volatiles compounds that evaporate at low temperatures couldnt accumulate here under the Suns constant bombardment.

The dark equatorial band. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Incidentally, the icy worlds elliptical orbit means that it moves between 50 Earth-Sun distances at its furthest point from the Sun and 30 Earth-Sun distances at its nearest point. Consequently, the temperature difference between a distant summer and a closer summer are more extreme than almost anywhere else.

This is all still relative, mind you: a summertime peak temperature is still around -200C (-330F). As Pluto takes 248 Earth years to rotate around the Sun, these summers and winters last for more than a century.

A second paper presented at the conference reveals that Plutos atmospheric pressure has varied wildly over its history, driven by these long-term orbital and rotational changes. It has ranged from about one-ten-thousandth right up to up to one-fifth of Earths.

These enormous changes in atmospheric pressure would have a distinct effect on the surface of the world; at higher pressures, the abundant nitrogen at the surface would remain a liquid instead of a gas. This means rivers, floods and lakes of liquid nitrogen may haved existed on Pluto.

Researchers noted that these features would be relatively common around 800,000 years ago, when temperatures were hot enough to lead to widespread melting. There may be some still around today near the equatorial region, although they have yet to be spotted. Frozen lakes, however, have been seen, and these ice reservoirs were almost certainly once liquid.

An enhanced color image of Pluto highlighting its wildly varying geological features. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Pluto is the gift that just keeps on giving, it seems. A plethora of papers have recently revealed that Plutos atmosphere isnt disintegrating as much as we previously thought, and most significantly, the surface is active essentially meaning that mountain building and perhaps cryovolcanism is still happening on this distant, icy sphere.

Above is a video of the research presented from the LPSC.

Photo Gallery

Read more: http://www.iflscience.com/space/pluto-has-rivers-liquid-nitrogen-extreme-seasons-and-chaotic-atmosphere

Blizzard Reserves Full Fury for Canadian Meteorologists During Live Report

The blizzard that bypassed New York City on Tuesday night went on to became one of the strongest winter storms to churn the waters of the Northwest Atlantic Ocean, striking Canada with its full fury.

he storm slammed the Canadian provinces of Nova Scotia, Prince Edward Island and Newfoundland, bringing winds equivalent to a Category 3 hurricane, waves that exceeded 45 feet in height, and close to two feet of wind-blasted snow.

The storm was so strong that reporters for The Weather Network, the Canadian equivalent to The Weather Channel, had trouble battling the elements during their live shots. In this video, Weather Network meteorologists Chris Scott and Mark Robinson were wiped out of camera-range at about the one minute mark during a report from Grand Etang, Nova Scotia.

According to Weather Underground chief meteorologist Jeff Masters, Grand Etang recorded peak sustained winds of 70 miles per hour, with gusts to 102 miles per hour. This location, Masters said, can experience especially strong southeast winds enhanced by nearby terrain. “These southeasterly winds travel up over Cape Breton and a funneling effect intensifies them as they blow downslope toward the Gulf of St. Lawrence,” he said in a blog post on Thursday.

The storm was noteworthy for intensifying so quickly, going from an ordinary low pressure system to a monstrous storm with a central pressure of 955 millibars — which is about as strong as a winter storm can get in this area.

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Visible satellite image of the blizzard on March 26

Read more: http://mashable.com/2014/03/27/blizzards-wipes-out-two-canadian-reporters/

Antarctic Ice Melt Rate Has Doubled Since 2010, Study Finds

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A glacial ice shelf seen from the air.
Image: NASA Operation IceBridge

A European Space Agency satellite has found that Antarctica has been shedding ice at an accelerated pace compared to when the continent was last surveyed, backing up other research that has detected similar trends. The study, accepted for publication in the journal Geophysical Research Letters, comes one week after other studies claimed that the “collapse” of some glaciers in the West Antarctic Ice Sheet may be inevitable, due to manmade global warming and other factors.

The new research, by a team of researchers in the U.K., used observations from the CryoSat-2 satellite to produce the first estimate of the volume and mass change of nearly the entire Antarctic ice sheet. The data used in the study included more than 455,000 independent estimates of changes in the land elevation of the vast ice sheets covering Antarctica, both in the western part of the continent, where ice is melting more rapidly, and in the east, where the ice is considered to be more stable, for the time being at least.

Three years of observations, between 2010 and 2013, from the CryoSat-2 satellite show that the Antarctic ice sheet is now losing about 160 billion metric tons of ice each year –- twice as much as when it was last surveyed during the 2005 to 2010 period.

Elevation Changes

Recent land elevation changes via the CryoSat-2 satellite, showing the greatest amount of sinking land in West Antarctica.

Image: European Space Agency

The CryoSat-2 satellite, which is operated by the European Space Agency, uses high-tech altimeter instruments to detect changes in the height of the ice sheet, and see whether it is gaining or losing mass.

According to the study, the average elevation of the Antarctic ice sheet fell by 0.74 inches per year between 2010 and 2013. However, far more rapid rates of land elevation changes, which are a sign of a thinning ice sheet that is discharging more water into the ocean and thereby raising global sea levels, occurred in West Antarctica, the study found.

In the Amundsen Sea Embayment region of West Antarctica, where glaciers terminate in the ocean and extend over the waters via floating ice tongues, six major glaciers are experiencing rapid rates of retreat. These glaciers are being eaten away from underneath due to warm ocean waters that have been driven toward the continent by shifting wind patterns that have in turn been linked to manmade global warming, as well as natural climate variability. For example, the Smith Glacier has been sinking at nearly 30 feet per year, the Cryosat data showed.

“We find that ice losses continue to be most pronounced along the fast-flowing ice streams of the Amundsen Sea sector, with thinning rates of 4 to 8 meters per year near to the grounding lines –- where the ice streams lift up off the land and begin to float out over the ocean –- of the Pine Island, Thwaites and Smith Glaciers,” said lead author Malcolm McMillan of the University of Leeds in the U.K. in a press release.

Using observations of recent rates of ice loss and model-based projections of the future, two studies published in scientific journals last week found that a slow-motion “collapse” of parts of the West Antarctic Ice Sheet may be inevitable, due in large part to manmade climate change and other factors. This could raise average global sea level by up to 15 feet, inundating highly populated coastal areas around the world.

The new study does not explicitly address that conclusion, but it does underscore the rapid melting that is taking place in the West Antarctic Ice Sheet in particular. In West Antarctica, the satellite data shows a mass loss of about 134 billion metric tons of ice per year, which is 31% greater than over the 2005 to 2011 period.

“Our results are in broad agreement with these previous studies. We detect widespread thinning of this part of the West Antarctic Ice Sheet, which is what you would be expect to see from an ice sheet in a state of irreversible long-term collapse,” said Malcolm McMillan, a research fellow at the University of Leeds, in an email to Mashable. “I should add that our study focuses on providing an up-to-date assessment of how the ice sheet has changed in the last 3 years, whereas one of the previous studies… uses models to investigate how the ice sheet may evolve in the future.”

East Antarctica is losing a relatively small amount of 3 billion metric tons of ice per year, the study found, and McMillan described that part of Antarctica as “roughly in balance.”

Sea Level Rise

Projections of global mean sea level rise over the 21st century, based on different emissions scenarios.

Image: U.N. Intergovernmental Panel on Climate Change

Although the study did not find a significant change in the elevation of the interior East Antarctic Ice Sheet, it shows for the first time that the thinning of the Totten glacier in that region extends to the point where the ice meets the land surface below, known as the grounding line. Overall, the researchers found that West Antarctica, the Antarctic Peninsula and East Antarctica have all been losing mass, albeit at different rates.

The Antarctic Peninsula, which is the fastest-warming region on the continent, has been shedding about 23 billion metric tons of ice per year, the study found. Changes in snowfall amounts have helped balance out some of the ice losses there and especially in eastern Antarctica.

For Antarctica as a whole, the study found the current rate of ice sheet mass loss to be about 160 billion metric tons of ice per year. The extra water pouring into the sea is raising sea levels by about 0.1 inches per year, the study found.

That may seem small at first, but over time, especially when combined with other sources of sea level rise such as melting Greenland glaciers and the expansion of seawater as ocean temperatures increase, it adds up. In addition, there are no guarantees that the current rate will be maintained, since many studies have shown the likelihood of a higher rate of sea level rise as global warming continues.

“Antarctica is contributing more to sea level rise than previous measurements suggested. It is essential that we continue to monitor the ice sheet to understand how, and why, it is changing,” McMillan said. While the study only includes data for the past three years, the observations extend a longer satellite record that dates back to the early 1990s, McMillan said. This data helps scientists make conclusions about how Antarctica’s ice sheets are changing.

The most recent report from the U.N. Intergovernmental Panel on Climate Change projected a global average sea level rise of between about one to three feet, although that report did not take the new findings on Antarctic ice melt into account.

Read more: http://mashable.com/2014/05/19/antarctic-ice-melt-accelerating/

12 Face Freezingly Cool Snow Creations

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Jupiter’s Great Red Spot Is Shrinking

Jupiter

This true-color simulated view of Jupiter is composed of four images taken by NASA’s Cassini spacecraft.

Jupiter’s Great Red Spot — the most powerful storm in the solar system — is at its smallest observed size yet, and scientists aren’t sure why.

Recent Hubble Space Telescope images of the storm show that it is now 10,250 miles across, which is less than half the size of the storm in the late 1800s. At one point, scientists theorized that three Earths could fit inside the Great Red Spot, but today, only the width of one Earth could fit within the raging tempest. You can watch a Great Red Spot video for more views of the diminishing storm.

Jupiter Red Spot

Image: NASA ESA

As the spot diminishes, its shrinkage rate appears to be accelerating. Amateur observations from 2012 show the storm’s “waistline” is reducing by 580 miles a year, a little less than the driving distance from New York City to Cincinnati.

Nobody knows for sure why the Great Red Spot is getting smaller.

“One possibility is that some unknown activity in the planet’s atmosphere may be draining energy and weakening the storm, causing it to shrink,” Hubble officials wrote in a statement.

While the storm has been observed since the 1600s, astronomers didn’t discover the “downsizing” until 1930. The spot was estimated at 25,500 miles across in the late 1800s. A century later, the Voyager 1 and 2 flybys of Jupiter in 1979 revealed the spot’s longest axis had shrunk to 14,500 miles.

Hubble has tracked the shrinkage since arriving in Earth’s orbit in the 1990s. A 1995 image showed the storm was about 13,020 miles across, but by 2009, that had diminished to 11,130 miles.

“In our new observations, it is apparent that very small eddies are feeding into the storm,” Amy Simon, associate director for strategic science at NASA’s Goddard Space Flight Center, said in a statement. “We hypothesized that these may be responsible for the accelerated change, by altering the internal dynamics and energy of the Great Red Spot.”

A large storm on at least one other planet changed or disappeared in recent decades. The Voyager 2 spacecraft also captured images of a “Great Dark Spot” on Neptune during a flyby in 1989. The storm was not visible to Hubble when the telescope examined the planet in 1994.

Hubble astronomers, including Simon, will take part in a webcast about Jupiter’s shrinking Great Red Spot on May 22 at 4 p.m. EDT. Learn more about the live webcast here.

This article originally published at Space.com
here

Read more: http://mashable.com/2014/05/16/jupiters-red-spot-shrinking/

Finally, Good Environmental News: The Ozone Layer Is Recovering

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Solar panels cover the roof of a Sam’s Club store on Earth Day, April 22, 2009 in Glendora, California.
Image: David McNew/Getty Images

Remember the hole in the ozone layer? The one caused by refrigerants used in air conditioners and aerosol spray cans?

Yeah, that never really went away.

Each frigid Antarctic winter, the ozone hole has reappeared, allowing higher amounts of ultraviolet rays from the sun to reach the Earth’s surface. Some years, such as in 2011, a significant hole even opens up over the Arctic, too.

Largest Ozone Hole

Total ozone concentrations (in Dobson Units) during the peak of the largest ozone hole ever recorded, in 2006.

Image: NASA

But finally, after years of cutting emissions of ozone-depleting substances known as Chlorofluorocarbons, or CFCs, and halons, scientists are detecting signs of recovery in the thin upper reaches of the stratosphere, according to a major U.N. report released Wednesday.

In other words, that problem you may have thought was fixed is now in fact well on its way toward being fixed.

But there’s a catch. Many of the substances that industry used to replace the harmful CFCs, such as hydrofluorocarbons, or HFCs, and hydroclorofluorocarbons, or HCFCs, don’t harm ozone, but turned out to be potent global warming gases.

By using them at an increasing rate, there’s a risk that gains in solving one environmental problem will inadvertently aggravate another, according to the report.

“The world avoided a major problem by getting rid of ozone-depleting substances via the Montreal Protocol,” said Achim Steiner, the director of the United Nations Environment Program (UNEP), at a press conference in New York. “We are at a critical point.”

The Montreal Protocol, a 1987 global agreement that mandated cuts to CFC emissions, has been one of the most successful environmental treaties in history.

According to the report, which is the first comprehensive update in global ozone science in four years, without the Montreal Protocol and its associated incremental agreements, atmospheric levels of ozone depleting substances could have increased tenfold by 2050. The Protocol will have prevented 2 million cases of skin cancer annually by 2030, the U.N. says, in addition to averting damage to human eyes and immune systems, and protecting wildlife and agriculture that are sensitive to UV radiation.

The report was the result of research by thousands of scientists around the world, and nearly 300 authors. Paul Newman, a NASA scientist who co-chairs the scientific assessment panel to the Montreal Protocol, said the stratospheric ozone layer is on the mend — especially in the upper reaches of the stratosphere, about 30 miles up. (For comparison, jet aircraft typically cruise at about six to eight miles high.)

These gains took decades of emissions reductions, however, illustrating how long it can take to solve a global environmental problem. In fact, as recently as the turn of the century, while CFC emissions were decreasing, the ozone hole was still increasing.

The ozone hole didn’t reach its peak size until 2006, when it was a whopping 10.6 million square miles, according to NASA. This is because CFCs and other ozone-depleting substances take many years to break down after reaching the stratosphere.

The report says the Antarctic ozone hole will continue to occur each spring throughout the century, even after CFC and halon emissions cease altogether.

“We now have the early hints that the ozone layer may be healing itself,” Newman said. The report predicts that stratospheric ozone should return to its 1980 level, which predates the decline in ozone, by about the year 2030.

Because CFCs warm the climate, the Montreal Protocol helped fight climate change — although that was never its intent, Steiner said.

On the other hand, emissions from their replacements, HFCs, are increasing by 7% per year. If this trend continues, Steiner says, we could have a “major challenge in terms of global warming” by 2050.

Numerous countries, including the U.S., are negotiating within the Montreal Protocol talks to enact limits on HFCs, but no binding reductions have been passed yet. There is a risk, Steiner says, that “by solving one problem, we will amplify another one.”

HFCs may be a topic of discussion at the upcoming UN Climate Summit in New York on September 23.

A.R. (Ravi) Ravishankara, who also co-chairs the scientific assessment, said that there is a risk that countries could enact curbs in carbon dioxide emissions to reduce global warming, but neglect to slash HFCs. “If you continue to emit HFCs, it could easily offset all the work you have done,” he said.

Alternatives to HFCs, which have less of an impact on the climate, could instead be used, if the Montreal Protocol is amended to encourage their production and distribution.

“Actions taken today could avoid buildup of HFCs,” he said.

Read more: http://mashable.com/2014/09/10/the-ozone-layer-is-finally-recovering-but-gains-are-fragile-with-links-to-climate-scientists-say/

Loss of Antarctic Ice Causing Gravity Dips

Loss of ice in Antarctica has been discussed extensively due to its implications for rising sea levels and the changing landscape of the continent, but it turns out that there is another unexpected effect: dips in gravity.

The ESA’s Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite obtained high-resolution measurements of Antarctica’s gravitational field between November 2009 and June 2012. Recent analysis led by Johannes Bouman of the German Geodetic Research Institute found that where the ice has been receding, so has the gravity field. The paper has been published in the journal Geophysical Research Letters

In order to monitor the melting, draining, and regrowth of Antarctica’s ice more precisely, it has been divided up into catchment basins. GOCE is the first instrument sensitive enough to detect local changes in gravity specific to each individual basin. Additionally, GOCE’s data provides geologists with insights into earthquakes and volcanic activity.

GOCE’s measurements were combined with data from NASA’s Gravity Recovery and Climate Experiment (GRACE), an older satellite whose readings are more coarse. Together, they were able to generate an extremely accurate and detailed model of Earth’s gravity field, even exploring the differences between the upper mantle and crust of the planet, as well as determining the upper atmosphere’s density.

This is the 2011 GOCE geoid that represents variations in height. Copyright ESA/HPF/DLR

This gravity model can be incorporated with data collected from ESA’s CryoSat satellite, which is a radar altimeter used to record depth of Arctic and Antarctic ice, as well as variations in sea levels. This will allow scientists to have a better understanding of this ever-changing landscape. 

Due to the effects of climate change, Antarctica is losing ice mass at an unprecedented rate. Every year since 2009, the rate of ice melt has increased by a factor of three from the previous year. There has been a loss in ice volume of about 125 cubic kilometers (78 cubic miles) of ice each year for the last three years. This loss was well reflected within the GOCE/GRACE gravity model and could be used to predict losses in the future as well. 

“We are now working in an interdisciplinary team to extend the analysis of GOCE’s data to all of Antarctica,” Bouman said in a press release. “This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass.”

Read more: http://www.iflscience.com/environment/loss-antarctic-ice-causing-gravity-dips-0