Antarctic Ozone Layer is Healing

Scientists at MIT and elsewhere have identified the "first fingerprints of healing" of the Antarctic ozone layer.

The team found that the September ozone hole has shrunk by more than 4 million square kilometers -- about half the area of the contiguous United States -- since 2000, when ozone depletion was at its peak. The team also showed for the first time that this recovery has slowed somewhat at times, due to the effects of volcanic eruptions from year to year. Overall, however, the ozone hole appears to be on a healing path.

The ozone hole was first discovered using ground-based data that began in the 1950s. Around the mid-1980s, scientists from the British Antarctic survey noticed that the October total ozone was dropping. From then on, scientists worldwide typically tracked ozone depletion using October measurements of Antarctic ozone.

Ozone is sensitive not just to chlorine, but also to temperature and sunlight. Chlorine eats away at ozone, but only if light is present and if the atmosphere is cold enough to create polar stratospheric clouds on which chlorine chemistry can occur -- a relationship that Solomon was first to characterize in 1986. Measurements have shown that ozone depletion starts each year in late August, as Antarctica emerges from its dark winter, and the hole is fully formed by early October.

The researchers tracked the yearly opening of the Antarctic ozone hole in the month of September, from 2000 to 2015. They analyzed ozone measurements taken from weather balloons and satellites, as well as satellite measurements of sulfur dioxide emitted by volcanoes, which can also enhance ozone depletion. And, they tracked meteorological changes, such as temperature and wind, which can shift the ozone hole back and forth.

They then compared their yearly September ozone measurements with model simulations that predict ozone levels based on the amount of chlorine that scientists have estimated to be present in the atmosphere from year to year. The researchers found that the ozone hole has declined compared to its peak size in 2000, shrinking by more than 4 million square kilometers by 2015. They further found that this decline matched the model's predictions, and that more than half the shrinkage was due solely to the reduction in atmospheric chlorine.

Extensive Ice Loss from Huge Antarctic Glacier

According to a new study, current rates of climate change could trigger instability in a major Antarctic glacier, ultimately leading to more than 2m of sea-level rise. That will be the same fate for the Totten Glacier, a significant glacier in Antarctica. Totten Glacier drains one of the world's largest areas of ice, on the East Antarctica Ice Sheet.

By studying the history of Totten's advances and retreats, researchers have discovered that if climate change continues unabated, the glacier could cross a critical threshold within the next century, entering an irreversible period of very rapid retreat. This would cause it to withdraw up to 300 km inland in the following centuries and release vase quantities of water, contributing up to 2.9 meters to global sea-level rise.

This is currently thought to be relatively stable in the face of global warming compared with the much smaller ice sheet in West Antarctica, but Totten Glacier is bucking the trend by losing substantial amounts of ice. The new research reveals that Totten Glacier may be even more vulnerable than previously thought.

Climate Predicts Bird Populations

According to an international study, population  of the most common bird species in Europe and the US are being altered by climate change.

For the first time researchers showed climate to be having a similar significant impact on bird population in large distant areas of the world. Their study used population-predicting models and three decades of field data, gathered by bird-watching volunteers..

Using annual climate records from 1980 to 2010 these models were able to predict where a species had experienced an improvement or a decline in suitable climate.

Source: Science

Human carbon release rate is unprecedentedd in the past 66 million years of Earth's history

Researchers look at changes of Earth's temperature and atmospheric carbon dioxide (CO2) since the end of the age of the dinosaurs. Their findings suggest humans are releasing carbon about 10 times faster than during any event in the past 66 million years.

The earliest instrumental records of Earth's climate, as measured by thermometers and other tools, start in the 1850s. To look further back in time, scientists investigate air bubbles trapped in ice cores, which expands the window to less than a million years. But to study Earth's history over tens to hundreds of millions of years, researchers examine the chemical and biological signatures of deep sea sediment archives.

Source: Nature Geo-science

Greenland melting tied to Shrinking Arctic Sea Ice

Ice of the arctic sea is vanishing, the weather systems over Greenland is dogged and the far-flung surface ice melting on the massive island.These dramatic trends and global sea-level rise are linked according to the study. 

During Greenland summers, melting Arctic sea ice favors stronger and more frequent blocking-high pressure systems, which spin clockwise, stay largely in place and can block cold, dry Canadian air from reaching the island. The highs tend to enhance the flow of warm, moist air over Greenland, contributing to incresed extreme heat events and surface ice melting, according to the study.

Source: Journal of Climate

Sun's activity controls Greenland Temperature

According to a new study the Sun's activity could be affecting a key ocean circulation mechanism that plays an important role in regulating Greenland's climate according to a new study. The phenomenon could be responsible for cool temperatures the island experienced in the late 20th century and potentially lead to increased melting of the Greenland ice sheet in the coming decades;

According to the climate scientist Takuro Kobashi, around starting 2025, temperature of the Greenland will be much higher than it was previously anticipated and the ice sheet could melt faster than projected. 

2014 is the warmest year on record

A report compiled by the NOAA's center for weather and climate at the National centers for environmental information is based on contributions from 413 scientists form 58 countries of the world. It provided the detailed update on global climate indicators, notable weather events, and other data collected by environmental monitoring stations and instruments located on land, water, ice and in space.

The Key highlight on the report include:

• Greenhouse Gases continued to climb: Carbon Di Oxide, Methane and Nitrous Oxide continued to rise during 2014 period. Atmospheric CO2 concentration increases by 1.9 ppm in 2014, reaching a global average of 397.2 ppm for the year.
• Record temperatures observed near the earth's surface: Four independent global datasets showed that 2014 was the warmest year on record. The warmth was widespread across land areas. Europe was the warmest continent on record in this year 2014. 20 countries Europe crossed their previous records. Africa's almost every country crossed above average temperate throughout 2014. Australia saw third warmest year on record. Mexico saw their first warmest year on record. Argentina and Uruguay saw their second warmest. Eastern North America was the only major region to experience below-average annual temperature.
• Tropical Pacific Ocean moves towards El-Nino Southern Oscillation conditions: The El Nino Southern Oscillation was in a nutral state in 2014 , although it was on the cool side in thee beginning of the year and approached warm El Nino conditions by the end of the year. The pattern played a major role in several regional climate outcomes.
• Sea surface temperatures were record high: The global averaged sea surface temperature was the highest on record. The warmth was particularly notable in the North Pacific Ocean.
• Global Upper ocean heat content was record high: Globally, the upper ocean heat content reached a record high for the year, reflecting the continuing accumulation of thermal energy in the upper layer of the oceans. Oceans absorb over 90% of earth's excess heat from greenhouse gas forcing.
• Global sea level was record high: Global average sea level rose to a record high in 2014. This keeps pace with the 3.2+/- 0.4 mm per year trend in sea level growth observed over past two decades.
• The Arctic continued to warm: The arctic experience its warmest year in record. Arctic snow melt occurred 20-30 days earlier than the 1998-2010 average.
• The antarctic shows highly variable temperature pattern: Some regions are cooler than normal and some are warmer than normal. Resulting a near-average condition as a whole. This 2014 is the third consecutive year of record maximum sea ice extent.
• Tropical cyclone above average overall: There are 91 cyclones in 2014 which is well above the average of 82 storms 

Heatwave in Pakistan's Sindh killed 224 people

Some 224 people are now believed to have died during a heatwave in Pakistan's southern Sindh province.

Health officials say most of the deaths have been in the largest city, Karachi, which has experienced temperatures as high as 45C (113F) in recent days. 

The city has seen power cuts caused by an increased demand for electricity because of the extreme weather.

Many of the victims are elderly people who have been suffering from fever, dehydration and gastric problems. 

Hundreds of patients suffering from the effects of the heatwave are being treated at government hospitals, provincial health secretary Saeed Mangnejo said.

 

Local media report that more than 150 bodies have been taken since Saturday to the Edhi morgue in Sohrab Goth, which usually receives about 20 bodies a day.

The demand for electricity for air conditioning has coincided with increased power needs over Ramadan, when Muslims fast during daylight hours.

Hot weather is not unusual during summer months in Pakistan, but prolonged power outages seem to have made matters worse, the BBC's Shahzeb Jillani reports.

Sporadic angry protests have taken place in parts of the city, with some people blaming the government and the city's main power utility, K-Electric, for failing to avoid deaths, our correspondent says.

Source: BBC News

Sea life 'must swim faster to survive' to survive climate change

Fish and other sea creatures will have to travel large distances to survive climate change, international marine scientists have warned. Sea life, particularly in the Indian Ocean, the Western and Eastern Pacific and the subarctic oceans will face growing pressures to adapt or relocate to escape extinction, according to a new study. 

Sea life, particularly in the Indian Ocean, the Western and Eastern Pacific and the subarctic oceans will face growing pressures to adapt or relocate to escape extinction, according to a new study by an international team of scientists published in the journal Science.
"Our research shows that species which cannot adapt to the increasingly warm waters they will encounter under climate change will have to swim farther and faster to find a new home," says team member Professor John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland.
Using 50 years' data of global temperature changes since the 1960s, the researchers analysed the shifting climates and seasonal patterns on land and in the oceans to understand how this will affect life in both over the coming century.
"We examined the velocity of climate change (the geographic shifts of temperature bands over time) and the shift in seasonal temperatures for both land and sea. We found both measures were higher for the ocean at certain latitudes than on land, despite the fact that the oceans tend to warm more slowly than air over the land."
The finding has serious implications especially for marine biodiversity hotspots -- such as the famous Coral Triangle and reefs that flourish in equatorial seas, and for life in polar seas, which will come under rising pressure from other species moving in, the team says.
"Unlike land-dwelling animals, which can just move up a mountain to find a cooler place to live, a sea creature may have to migrate several hundred kilometres to find a new home where the water temperature, seasonal conditions and food supply all suit it," Prof. Pandolfi says.
Under current global warming, land animals and plants are migrating polewards at a rate of about 6 kilometres a decade -- but sea creatures may have to move several times faster to keep in touch with the water temperature and conditions that best suit them. Team member Associate Professor Anthony Richardson from the School of Mathematics and Physics at the University of Queensland became interested in how species might respond to climate change during his work on a global synthesis of marine climate impacts.
He says, "We have been underestimating the likely impact of climate change on the oceans." As a general rule, it seems sea life will have to move a lot faster and farther to keep up with temperature shifts in the oceans. This applies especially to fish and marine animals living in the equatorial and subarctic seas, and poses a particular issue both for conservation and fisheries management. Assoc. Professor Richardson explains, "There is also a complex mosaic of responses globally, related to local warming and cooling. For example, our analysis suggests that life in many areas in the Southern Ocean could move northward." However, as a rule, they are likely to be as great or greater in the sea than on land, as a result of its more uniform temperature distribution.
The migration is likely to be particularly pronounced among marine species living at or near the sea surface, or subsisting on marine plants and plankton that require sunlight -- and less so in the deep oceans.
"Also, as seas around the equator warm more quickly and sea life migrates away -- north or south -- in search of cooler water, it isn't clear what, if anything, will replace it," Prof Pandolfi adds. "No communities of organisms from even warmer regions currently exist to replace those moving out."
At the same time, sea life living close to the poles could find itself overwhelmed by marine migrants moving in from warmer regions, in search of cool water.
The team's future research will focus on how different ocean species respond to climate change and they are compiling a database on this for the Intergovernmental Panel on Climate Change (IPCC).

This story is taken from Science Daily

Few opportunities to change: Ocean warming, oxygen loss putting marine life under increasing pressure

If you want to live, you need to breathe and muster enough energy to move, find nourishment and reproduce. This basic tenet is just as valid for us human beings as it is for the animals inhabiting our oceans. Unfortunately, most marine animals will find it harder to satisfy these criteria, which are vital to their survival, in the future. 

In order to be able to make more precise and globally applicable prognoses concerning the effects of climate change on life in our oceans, marine biologists have long sought to find universal principles that would allow them to describe the living conditions in the oceans and at their borders. In this regard, one of the key questions is: How will the warming of the oceans and resultant decrease in dissolved oxygen impact marine life forms' productivity? As marine biologist Prof Hans-Otto Pörtner from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Science, who co-authored the article, explains, "If an animal has to do more work, it costs energy that it somehow has to produce over and above its resting metabolic rate. Marine life forms generate this additional energy by breathing and thereby taking up more oxygen. However, their ability to do so depends on two factors: the water temperature, and how sensitive the species is to lack of oxygen."
In their new study, he and his American colleagues Curtis Deutsch, Brad Seibel, Aaron Ferrel and Raymond B. Huey calculated the ability of selected animal species to increase their metabolic rate, then examined that ability in relation with the temperatures and oxygen concentrations in the world's oceans. This approach allowed them to create a metabolic index for each species, which sets clearly defined limits for oxygen-breathing sea life: "Marine animals like eelpouts, rock crabs and Atlantic cod can only survive in environments with enough oxygen for them to increase their metabolism to between two and five times their resting metabolic rate if need be. Every species has a certain maximum temperature to survive, and a certain minimum oxygen level, and the two requirements are related," says lead author Curtis Deutsch from the University of Washington.
As such, the ongoing climate change poses the following problem for marine animals: the warmer the water gets, the less oxygen it can absorb and store. At the same time, in warmer water the animals will need more energy and oxygen to maintain their resting metabolic rate. This means the warmer the oceans become, the less able its inhabitants will be to boost their metabolism to between two and five times their resting metabolic rate, which is what allows them to move, seek food and reproduce. "If the oxygen level in a given region of the ocean drops below a species' minimum requirements, it forces the animals to abandon their native habitat. This combines with the effect of warmer temperatures. Since animals evade to cooler regions, their habitat shifts towards the poles or to greater water depths. In Atlantic cod and many other fish species, we can already observe the shift now," says Hans-Otto Pörtner.
In their study, the authors provide habitat-shift prognoses for all latitudes. As Hans-Otto Pörtner adds: "Further, the phenomenon is even more pronounced in those regions hit by additional oxygen loss, for instance due to increasing water stratification or because human beings release more nutrients into the ocean, promoting the growth of oxygen-stealing microorganisms."
The researchers expect to see the most apparent changes in the polar seas. "The water in the Arctic and Antarctic Oceans is extremely cold, but also very rich in oxygen. Thanks to evolution, the animals living there have adapted to these conditions and will have little chance to adjust when the combination of warming and lower oxygen levels hits. Instead, species that immigrate from areas with higher water temperatures and lower oxygen concentrations will establish themselves and displace the native polar species," says Hans-Otto Pörtner.
In the northern Pacific, for example, researchers are already observing a more extreme drop in oxygen concentrations than was expected due to warming alone. In this type of ocean region, the species' geographic range is reduced drastically, which of course also means significant consequences for the fishing industry.
From a research perspective, the new metabolic index concept can potentially facilitate better prognoses. "We now have a universal approach that allows us to more precisely identify climate-related changes in the geographic range and productivity of a given species," explains Hans-Otto Pörtner. Now it's up to the scientific community to investigate the metabolic index and its limits for further species; if they do, Pörtner is confident that: "Bit by bit, we'll arrive at a far more complete image of what we outlined in our study."

This story is taken from Science Daily

Extreme global warming of Cretaceous period punctuated with significant global cooling

Scientists have reconstructed the climatic development of the Arctic Ocean during the Cretaceous period, 145 to 66 million years ago. At that time the poles were devoid of ice and average temperatures of up to 35 degrees Celsius prevailed in the oceans. Yet new research shows there was a severe cold snap during the geological age known for its extreme greenhouse climate. What sparked the abrupt global cooling? 

The Cretaceous, which occurred approximately 145 million to 66 million years ago, was one of the warmest periods in the history of Earth. The poles were devoid of ice and average temperatures of up to 35 degrees Celsius prevailed in the oceans. "A typical greenhouse climate; some even refer to it as a 'super greenhouse' ," explains Professor Dr. Jens Herrle of the Goethe University and Senckenberg Biodiversity and Climate Research Centre, and adds: "We have now found indications in the Arctic that this warm era 112 to 118 million years ago was interrupted for a period of about 6 million years."
In cooperation with his Canadian colleague Professor Claudia Schröder-Adams of the Carleton University in Ottawa, the Frankfurt palaeontologist sampled the Arctic Fjord Glacier and the Lost Hammer diapir locality on Axel Heiberg Island in 5 to 10 metre intervals. "In so doing, we also found so-called glendonites," Herrle recounts. Glendonite refers to star-shaped calcite minerals, which have taken on the crystal shape of the mineral ikaite. "These so-called pseudomorphs from calcite to ikaite are formed because ikaite is stable only below 8 degrees Celsius and metamorphoses into calcite at warmer temperatures," explains Herrle and adds: "Thus, our sedimentological analyses and age dating provide a concrete indication for the environmental conditions in the cretaceous Arctic and substantiate the assumption that there was an extended interruption of the interglacial period in the Arctic Ocean at that time."
In two research expeditions to the Arctic undertaken in 2011 and 2014, Herrle brought 1700 rock samples back to Frankfurt, where he and his working group analysed them using geochemical and paleontological methods. But can the Cretaceous rocks from the polar region also help to get a better understanding of the current climate change? "Yes," Herrle thinks, elaborating: "The polar regions are particularly sensitive to global climatic fluctuations. Looking into the geological past allows us to gain fundamental knowledge regarding the dynamics of climate change and oceanic circulation under extreme greenhouse conditions. To be capable of better assessing the current human-made climate change, we must, for example, understand what processes in an extreme greenhouse climate contribute significantly to climate change." In the case of the Cretaceous cold snap, Herrle assumes that due to the opening of the Atlantic in conjunction with changes in oceanic circulation and marine productivity, more carbon was incorporated into the sediments. This resulted in a decrease in the carbon dioxide content in the atmosphere, which in turn produced global cooling.
The Frankfurt scientist's newly acquired data from the Cretaceous period will now be correlated with results for this era derived from the Atlantic, "in order to achieve a more accurate stratigraphic classification of the Cretaceous period and to better understand the interrelationships between the polar regions and the subtropics," is the outlook Herrle provides.

This story is taken from Science Daily

Global warming skeptics unmoved by extreme weather

What will it take to convince skeptics of global warming that the phenomenon is real? Surely, many scientists believe, enough droughts, floods and heat waves will begin to change minds. But a new study throws cold water on that theory. 

But a new study led by a Michigan State University scholar throws cold water on that theory.
Only 35 percent of U.S. citizens believe global warming was the main cause of the abnormally high temperatures during the winter of 2012, Aaron M. McCright and colleagues report in a paper published online today in the journal Nature Climate Change.
"Many people already had their minds made up about global warming and this extreme weather was not going to change that," said McCright, associate professor in MSU's Lyman Briggs College and Department of Sociology.
Winter 2012 was the fourth warmest winter in the United States dating back to at least 1895, according to the National Oceanic and Atmospheric Administration. Some 80 percent of U.S. citizens reported winter temperatures in their local area were warmer than usual.
The researchers analyzed March 2012 Gallup Poll data of more than 1,000 people and examined how individuals' responses related to actual temperatures in their home states. Perceptions of warmer winter temperatures seemed to track with observed temperatures.
"Those results are promising because we do hope that people accurately perceive the reality that's around them so they can adapt accordingly to the weather," McCright said.
But when it came to attributing the abnormally warm weather to global warming, respondents largely held fast to their existing beliefs and were not influenced by actual temperatures.
As this study and McCright's past research shows, political party identification plays a significant role in determining global warming beliefs. People who identify as Republican tend to doubt the existence of global warming, while Democrats generally believe in it.
The abnormally warm winter was just one in an ongoing series of severe weather events -- including the 2010 Russian heat wave, Hurricane Sandy in 2012 and the 2013 typhoon in the Philippines -- that many believed would help start convincing global warming skeptics.
"There's been a lot of talk among climate scientists, politicians and journalists that warmer winters like this would change people's minds," McCright said. "That the more people are exposed to climate change, the more they'll be convinced. This study suggests this is not the case."

This story is taken from Science Daily

Drastic Antarctic Melt could Double Global Sea-Level Rise

According to a article published on the BBC, Global sea levels could rise by more than double the current best estimate.

The modelling assessment says that Antarctic melting alone could contribute more than a metre to sea level by the end of this century.According to  the study, the same could cause levels across the world to rise by 13m. The rapid cuts in Carbon emissions could limit this risk.