Evidence of an astronomical "smoking gun" has been discovered that supports the idea that cosmic rays from a nearby supernova triggered at least one of the six mass extinctions on Earth. Luckily for us, the astronomers say, there is very little danger of it happening again anytime soon.

Narcisco Benítez at John Hopkins University in Baltimore, Maryland and Jesús Maíz Appellániz of the Space Telescope Science Institute in Virginia traced the motion of a cluster of young, short lived stars formed from the debris of around 20 supernova which have exploded over the last 20 million years.

The cluster, called the Scorpius-Centaurus OB association, is now positioned a safe 350 light-years from Earth. But the group says it passed within 130 light-years of Earth about two million years ago.

This puts it in the right place at the right time to explain evidence uncovered on Earth by German researchers in 1999. They found atoms of a very rare isotope of iron, ⁶⁰Fe, in cores taken from the ocean floor. ⁶⁰Fe is rare in the solar system because it has a half-life of 1.5 million years. The German group suggested that the iron arrived on Earth as fallout from a nearby supernova about two million years ago. This is about the time that fossil records indicate that many marine molluscs went extinct

The ozone layer was up to 30 per cent thinner over Europe during the first week of February and periodic depletions like this are becoming more frequent, say scientists at the European Space Agency (ESA).

The Global Ozone Monitoring Experiment (GOME) is mounted on ESA's ERS-2 satellite and has a spectrometer that measures UV radiation in the 240 to 790 nanometre region. Ozone has a signature peak at 325 to 335 nm.

"Over the last five years we have seen more of these ozone thinning episodes," says Diego Loyola from DLR, the German aerospace centre. "But we have only been monitoring since 1995 and we would need at least 20 years' worth of data to draw a firm conclusion."

The thinning resulted from streamers of tropical air from the equatorial regions - where ozone levels are lower - spreading up across southern Spain, France and Germany, decreasing the total ozone coverage.

Harmful rays

Coverage levels of below 250 Dobson units were seen - an ozone hole is classed as coverage below 200 Dobson units. The decreased ozone means an increased amount of harmful radiation from the Sun reaches people on the ground.

But Jonathan Shanklin, from the British Antarctic Survey and one of the team that discovered the Antarctic ozone hole, said that these low levels are not unusual and they have been much lower.

"They don't last for more than a few days and they are just one-tenth the size of the hole in Antarctica. But on clear days we are exposed to dangerous levels of UV rays," Shanklin told New Scientist

We live in a world that has become so desensitised by watching calamities unfold on global television - both natural and human-induced - that it takes something really spectacular even to get our attention.

And it usually has to be visually dramatic to register, much less elicit a deep emotional response - such as the tragic events of September 11.

Recently, I came across a frightening report published by the US National Academy of Sciences (NAS) - the nation's most august scientific body. Yet, because there was no visually provocative content, the report had received only a couple of short paragraphs tucked away inside a few newspapers.

Here is what the academy had to say: it is possible that the global warming trend projected over the course of the next 100 years could, all of a sudden and without warning, dramatically accelerate in just a handful of years - forcing a qualitative new climatic regime which could undermine ecosystems and human settlements throughout the world, leaving little or no time for plants, animals and humans to adjust.

The new climate could result in a wholesale change in the earth's environment, with effects that would be felt for thousands of years. If the projections and warnings in this study turn out to be prophetic, no other catastrophic event in all of recorded history will have had as damaging an impact on the future of human civilisation and the life of the planet.

A year ago the UN intergovernmental panel on climate change (IPCC) issued a voluminous report forecasting that global average surface temperature is likely to rise by 1.4 to 5.8 degrees centigrade between now and 2100. If that projection holds up, we were told, the change in temperature forecast for the next 100 years will be larger than any climate change on earth in more than 10,000 years.

The impacts on the earth's biosphere are going to be of a qualitative kind. To understand how significant this rise in temperature is likely to be, we need to keep in mind that a 5 degrees centigrade increase in temperature between the last ice age and today resulted in much of the northern hemisphere of the planet going from being buried under thousands of feet of ice to being ice-free.

The UN study predicts that a temperature rise of 1.4-5.8 degrees centigrade over the course of the coming century could include the melting of glaciers and the Arctic polar cap, sea water rise, increased precipitation and storms and more violent weather patterns, destabilisation and loss of habitats, migration northward of ecosystems, contamination of fresh water by salt water, massive forest dieback, accelerated species extinction and increased droughts.

The IPCC report also warns of adverse impacts on human settlements, including the submerging of island nations and low-lying countries, diminishing crop yields, especially in the southern hemisphere, and the spread of tropical disease northward into previously temperate zones.

The newly released NAS report begins by noting that the current projections about global warming and its ecological, economic and social impacts cited in the UN report are based on the assumption of a steady upward climb in temperatures, more or less evenly distributed over the course of the 21st century. But that assumption, they say, may be faulty - there is a possibility that temperatures could rise suddenly in just a few years' time, creating a new climatic regime virtually overnight.

They also point out that abrupt changes in climate, whose effects are long lasting, have occurred repeatedly in the past 100,000 years. For example, at the end of the Younger-Dryas interval about 11,500 years ago, "global climate shifted dramatically, in many regions by about one-third to one-half the difference between ice age and modern conditions, with much of the change occurring over a few years".

According to the study: "An abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause." Moreover, the paleoclimatic record shows that "the most dramatic shifts in climate have occurred when factors controlling the climate system were changing". Given the fact that human activity - especially the burning of fossil fuels - is expected to double the CO<->2 content emitted into the atmosphere in the current century, the conditions could be ripe for an abrupt change in climate around the world, perhaps in only a few years.

What is really unnerving is that it may take only a slight deviation in boundary conditions or a small random fluctuation somewhere in the system "to excite large changes ... when the system is close to a threshold", says the NAS committee.

An abrupt change in climate, of the kind that occurred during the Younger-Dryas interval, could prove catastrophic for ecosystems and species around the world. During that particular period, for instance, spruce, fir and paper birch trees experienced mass extinction in southern New England in less than 50 years. The extinction of horses, mastodons, mammoths, and sabre-toothed tigers in North America were greater at that time than in any other extinction event in millions of years.

The committee lays out a potentially nightmarish scenario in which random triggering events take the climate across the threshold into a new regime, causing widespread havoc and destruction.

Ecosystems could collapse suddenly with forests decimated in vast fires and grasslands drying out and turning into dust bowls. Wildlife could disappear and waterborne diseases such as cholera and vector-borne diseases such as malaria, dengue and yellow fever, could spread uncontrollably beyond host ranges, threatening human health around the world.

The NAS concludes its report with a dire warning: "On the basis of the inference from the paleoclimatic record, it is possible that the projected change will occur not through gradual evolution, proportional to greenhouse gas concentrations, but through abrupt and persistent regime shifts affecting subcontinental or larger regions - denying the likelihood or downplaying the relevance of past abrupt changes could be costly."

Global warming represents the dark side of the commercial ledger for the industrial age. For the past several hundred years, and especially in the 20th century, human beings burned massive amounts of "stored sun" in the form of coal, oil and natural gas, to produce the energy that made an industrial way of life possible. That spent energy has accumulated in the atmosphere and has begun to adversely affect the climate of the planet and the workings of its many ecosystems.

If we were to measure human accomplishments in terms of the sheer impact our activities have had on the life of the planet, then we would sadly have to conclude that global warming is our most significant accomplishment to date, albeit a negative one.

We have affected the biochemistry of the earth and we have done it in less than a century. If a qualitative climate change were to occur suddenly in the coming century - within less than 10 years - as has happened many times before in geological history, we may already have written our epitaph.

When future generations look back at this period, tens of thousands of years from now, it is possible that the only historical legacy we will have left them in the geologic record is a great change in the earth's climate and its impact on the biosphere.

May 9, 2002 — NOAA forecasters today said a weak or moderate El Niño event is likely to develop during the next six-to-nine months, but global impacts should be less than those experienced during the strong 1997-98 El Niño. (Click NOAA image to see latest sea surface temperatures.)

NOAA's Climate Prediction Center states that El Niño is still developing and will probably remain that way for the next several months, with abnormally warm ocean surface temperatures continuing over most of the central equatorial Pacific.

"Some events develop quickly and others, like this one, have a more gradual evolution," said Brig. Gen. Jack Kelly USAF (ret.), director of NOAA's National Weather Service. "We are maintaining a constant watch over the conditions of the atmosphere and ocean and will continue providing guidance on potential impacts," said Kelly.

In this month's El Niño/Southern Oscillation Diagnostic Discussion, NOAA scientists report that ocean surface temperatures were more than 0.5 degrees C (0.9 F) above average during April over a large part of the central equatorial Pacific and as much as 2 degrees C (3.6 F) above average in the extreme eastern equatorial Pacific. Also, subsurface ocean temperatures remained more than 2 degrees C (3.6 F) above normal in the central equatorial Pacific.

NOAA will continue monitoring El Niño's developments and provide monthly updates. The El Niño/Southern Oscillation Diagnostic Discussion is a team effort consisting of the Climate Prediction Center (lead), Climate Diagnostics Center, Geophysical Fluid Dynamics Laboratory, National Climatic Data Center, Atlantic Oceanographic and Meteorological Laboratory, and the International Research Institute for Climate Prediction.

NOAA's Climate Prediction Center is an organization of the National Weather Service. NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. The National Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy.

Relevant Web Sites

NOAA's Climate Prediction Center

El Niño/Southern Oscillation (ENSO) Diagnostic Discussion

Most Recent 2 Months Sea Surface Temperature Anomaly Animation

El Niño and La Niña-related Winter Features over North America

NOAA's El Niño Theme Page

NOAA's El Niño Home Page

CLIMATE FACTORS HELPING TO SHAPE WINTER 2001-2002

NOAA's CURRENT SEA SURFACE TEMPERATURE MAPS

ENSO Fact Sheet

ENSO Frequently Asked Questions

ENSO Tutorial

ENSO Recent Events

Sea Surface Temperature Outlook

ENSO Impacts by Region

Media Contact:
Carmeyia Gillis, NOAA's Climate Prediction Center, (301) 763-8000 ext. 7163

BUDAPEST, Hungary -- Thousands of people have been evacuated from their homes as unseasonably high flood waters threaten a large part of eastern Europe.

Areas of Hungary, Romania and the Ukraine are at risk from three rivers -- the Tisza, Tur and Szamos -- which have been swollen by heavy recent rain and melting snow.

The Tisza, Hungary's second largest river, rose by over six metres at the weekend as a result of rapidly melting snow and two days of rain in neighbouring Ukraine.

A state of emergency has been declared in Hungary after flood waters forced the evacuation of thousands of people.

On Tuesday, more than 7,000 people were evacuated from their flood-threatened homes in eight villages, the local news agency MTI reported.

Among them were hundreds of people evacuated from the village of Kispalad, which is adjacent to Hungary's boarders with Ukraine and Romania, after floodwaters broke through a dyke.

In Romania, about 1,600 people have been evacuated from their homes in 80 villages.

On Monday, another 7,000 fled their homes in western Ukraine to escape rising floodwaters.

Hungary's Transport Minister Janos Fonagy said 13,500 soldiers and volunteers were struggling to maintain flood defences on the rapidly rising rivers.

"The water levels are unprecedentedly high," Fonagy said. "Experts say we have to prepare for lasting floods."

In Ukraine, thousands of people in areas bordering Hungary were evacuated because of flooding.

At Ukraine's request, Hungary has opened a temporary border crossing at the village of Nagyhodos for Ukrainians fleeing the floods.

The Ukraine Emergency Ministry said its stretch of the Tisza burst its banks in several locations releasing millions of gallons of flood water into the valleys of the Carpathian Mountains.

At least 10 homes have been destroyed. "We have no gas, no drinking water and no one has come to help us," villager Marta Chedrych said.

World Meteorological Day celebrates the coming into force of the Convention of the World Meteorological Organization (WMO) on 23 March 1950. Last year's address was delivered by Dr Sharman Stone, MP, Parliamentary Secretary to the Minister for the Environment and Heritage, on the 2001 World Meteorology Day theme of Volunteers for Weather, Climate and Water. Dr Stone, who has Ministerial responsibility for the Australian Antarctic Division and the Bureau of Meteorology, welcomed Dr Solomon's visit to Australia for the 2002 address and for a number of other lectures and meetings on climate and climate change.

Dr Solomon was the first person to show that the primary cause of the ozone hole over Antarctica was the presence of chlorofluorocarbon (CFC) gases that have been used in refrigeration, air-conditioning, spray cans, and other products. Her discovery in the mid-1980s was instrumental in persuading the world to curtail the use of CFCs.

Ozone traps ultraviolet light from the sun and heats the stratosphere about 10-30 kilometres above the Earth. With less ozone, less heat is trapped, and the Antarctic stratosphere is now much colder. Growing levels of carbon dioxide in the atmosphere - the greenhouse effect - also act to cool the stratosphere, even though they warm the surface. The increasing chill in the stratosphere helps CFCs destroy ozone more efficiently, and may cause a slow increase in the size of the ozone hole in coming decades.

The climate at the surface of Antarctica has also changed in recent decades, becoming colder in the continent's interior but warming on the Antarctic Peninsula. The warning has led to spectacular changes in some of Antarctica's ice shelves.

Immediately before Dr Solomon's address, which will commence at 11.30am, the Director of Meteorology, Dr John Zillman, will welcome guests to the World Meteorological Day celebrations. Excellence and Long Service Awards to Bureau staff will be presented by former Ministers responsible for the Bureau, the Hon Peter Nixon and the Hon Barry Jones. Former Australian Ambassador for the Environment, the Rt Hon Sir Ninian Stephen will speak on behalf of the guests to thank Dr Solomon for her address.

• Massive Antarctic Ice Shelf Collapse!

A massive Antarctic ice shelf has collapsed into the sea, shattering into thousands of icebergs and alarming researchers by the speed with which the process unfolded. Described by one researcher as “staggering,” the rapid collapse offered fuel for the debate over whether global warming is to blame.

HOUSTON, TEXAS -- Our solar system may have had a fifth terrestrial planet, one that was swallowed up by the Sun. But before it was destroyed, the now missing-in-action world made a mess of things.

Space scientists John Chambers and Jack Lissauer of NASA's Ames Research Center hypothesize that along with Mercury, Venus, Earth, and Mars -- the terrestrial, rocky planets -- there was a fifth terrestrial world, likely just outside of Mars's orbit and before the inner asteroid belt.

Moreover, Planet V was a troublemaker.

The computer modeling findings of Chambers and Lissauer were presented during  the 33rd Lunar and Planetary Science Conference, held here March 11-15, and sponsored by NASA and the Lunar and Planetary Institute.

It is commonly believed that during the formative years of our solar system, between 3.8 billion and 4 billion years ago, the Moon and Earth took a pounding from space debris. However, there is an on-going debate as to whether or not the bruising impacts tailed off 3.8 billion year ago or if there was a sudden increase - a "spike" -- in the impact rate around 3.9 billion years ago, with quiet periods before and afterwards?

The great cover-up

Having a swarm of objects clobbering the Moon in a narrow point of time would have resurfaced most of our celestial next door neighbor, covering up its early history. Being that the Moon is so small, Earth would have been on the receiving end of any destructive deluge too.

Moon-walking astronauts brought back a cache of lunar material. Later analysis showed that virtually all impact rocks in the "Apollo collection" sported nearly the same age, 3.9 billion years, and none were older. But some scientists claim that these samples were "biased", as they came from a small area of the Moon, and are the result of a localized pummeling, not some lunar big bang.

There is a problem in having a "spike" in the lunar cratering rate.

That scenario is tough to devise. Things should have been settling down, according to solar system creation experts. Having chunks of stuff come zipping along some hundreds of millions of years later out of nowhere and create a lunar late heavy bombardment is a puzzler.

If real, what were these bodies, and where were they before they scuffed up the Moon big time? The answer, according to Chambers and Lissauer, might be tied to the the
Planet V hypothesis.

"The extra planet formed on a low-eccentricity orbit that was long-lived, but unstable," Chambers reported. About 3.9 billion years ago, Planet V was perturbed by gravitational interactions with the other inner planets. It was tossed onto a highly eccentric orbit that
crossed the inner asteroid belt, a reservoir of material much larger than it is today.

Planet V's close encounters with the inner belt of asteroids stirred up a large fraction of those bodies, scattering them about. The perturbed asteroids evolved into Mars crossing orbits, and temporarily enhanced the population of bodies on Earth-crossing orbits, and also increased the lunar impact rate.

After doing its destabilizing deeds, Planet V was lost too, most likely spinning into the Sun, the NASA team reported.

The temporary existence of more than 4 planet-sized bodies in the inner Solar System is consistent with the currently favored model for the formation of the Moon. Work by Chambers and Lissauer also supports the view that our Moon is a leftover of a massive collision between Earth and a Mars-sized body 50 million to 100 million years after the formation of the Solar System.

Striking Views

Wendell Mendell, a planetary scientist here at NASA's Johnson Space Center, said the new theory is intriguing.

"This idea and others within the last few years show that the Solar System is filled with all sorts of gravitational resonances...that a lot of potential orbits in the Solar System are chaotic and unstable," Mendell told SPACE.com. "My sense is that this is a new idea. It's another thing to throw into the pot that's not totally crazy."

The work suggests there's a match up in timing, Mendell said, with asteroids striking the Moon and causing the effects that are seen in the dating of Apollo lunar rocks.

"By thinking that the Solar System was really quite different in a major way with an extra inner planet, we might be able to develop some sort of self-consistent scenario that explains a lot of things. But all this is at the very early stages now," Mendell said.

"We're moving into a really new regime," Mendell added, "where the Solar System is not a static dynamic place from day one to now. It really might have had some nuances and synchronicities associated with it that we have not really tried to exploit before."

It takes a drill hole Setting the early Solar System and lunar history record straight means going back to the Moon.

"The Moon is still the keystone to our understanding of the Solar System," NASA's Mendell said.

That too is the view of Apollo 17 astronaut, Harrison "Jack" Schmitt. Getting back to the Moon to sort out the real story is a must, he said.

"You're going to have to be very, very specific on what sites you go to collect new samples," Schmitt told SPACE.com. "It may be very difficult to get an answer without using missions to fairly large impact craters that penetrate through the ejecta. Those impacts are sort of a drill hole into the lunar crust," he said.

Dating service

Places on the Moon where older, large basins have deposited ejecta are ideal research zones, Schmitt said. Digging into such sites could yield impact glass formed by basins perhaps dating older than 3.9 billion years old, he said.

Just taking spot samples -- say from the Moon's South Pole Aitken basin -- could be risky, in terms of uncovering the Moon's rocky history, Schmitt said. Such a huge area would take multiple robotic or human exploration missions, each with significant roving abilities.

Also known as the "Big Backside Basin," Aitken is the largest impact crater on the Moon, and one of the biggest in the Solar System.

For the near term, sets of low-cost, mini-robotic landers carrying specialized gear would be ideal in opening up the Moon to further exploration, Schmitt said.

"Numbers of targeted missions could get a lot of great information on some of these fundamental questions that we still haven't been able to answer," Schmitt said.

Getting back to the Moon with a settlement for resource exploitation is another step forward. From such a site, human explorers can survey various lunar locales - even the Moon's side that we Earthlings never see, Schmitt said. "Then we can do the kind of thing that Apollo did for the near side of the Moon," he said.

Dr Geoff Jenkins, director of the Meteorological Office's Hadley Centre, said the record on land and sea was consistent with computer predictions of the effects of man-made global warming.

The three months were about 0.71C warmer than the average for 1961 to 1990, itself the warmest period for 1,000 years according to ice-core analysis, he added.

The record warm period was the more remarkable because there was no sign of the cyclical El Nino in the tropics, which has attended the succession of record warmest years in the past decade.

The global record comes in the wake of observed changes in the British climate since 1900: a lengthening of the growing season for plants by one month in central England, a temperature increase of 1C, and a 10cm sea level rise.

Margaret Beckett, the Environment, Food and Rural Affairs Secretary, said: "In recent years more and more people have accepted that climate change is happening and will affect the lives of our children and grandchildren. I fear we need to start worrying about ourselves as well."

She was speaking at the publication of a report, The UK Climate Impacts Programme, a joint venture between her department, the Hadley Centre, and the Tyndall Centre for Climate Change Research at the University of East Anglia.

Scientists, who compiled different scenarios for high, medium and low emissions of greenhouse gases, predicted the following changes in the British climate by 2080:

• A rise in average temperature of 2-3.5C, probably with greater warming in the south and east. Generally, the climate will be like Normandy, the Loire or Bordeaux, according to the amount of global emissions.
• Hot days in summer will be more frequent, with some above 40C (104F) in lowland Britain under the high emissions scenario.
• Summer rainfall will decrease by 50 per cent and winter rainfall increase by 30 per cent under the highest emissions projection.
• Snowfall will decrease throughout Britain, by 90 per cent in Scotland according to the highest greenhouse gases scenario.
• Sea levels will rise by 26-86cm (10-34in).
• The probability of a storm surge regarded as extreme will increase from one in 50 years to nine in 10 years under the high emissions scenario.

A cooling of the British climate over the next 100 years because of changes to the Gulf Stream is now considered unlikely.

Mrs Beckett said some of the predicted impacts were already irreversible, but others could be slowed by international action under the Kyoto climate treaty.

22 March 2002: Tree rings may point to earlier global warming

20 March 2002: Giant ice sheet's break-up 'is a warning to world'

29 December 2001: Ice experts predict rise in sea levels

19 December 2001: Second warmest year on record