RENE VOSSLAMBER Herald correspondent 26th August 1997
This current (1997) El Nino could be brewing up something much worse than previously. It is measured both by water temperature on the eastern equator and by the Southern Oscillation index. Last april the oscillation became minus one (El Nino) now it is minus two, the same measurement as recorded in the 1982-83 crisis which caused 25 billion worth of damage worldwide. If it drops to minus three in the spring it will be the El Nino of the century. Although the jury is still out on whether El Nino is a product of global warming, there have been five in the last 20 years and only three in the previous 25. One thing is certain. This latest El Nino confirms a new weather phenomenon for the entire planet - we are now developing a string of El Ninos.
10 Oct 98 NS the whopping ozone hole three times the size of the US is blamed on El Nino's polar vortices. This comes in addition to the Earth's rotation having slowed because if increasing rotational momentum of the atmosphere due to El Nino.
Will El nino become El Hombre?
Lou Bergeron New Scientist 20 Jan 1996
EL NINO, "the little boy", has just thrown his longest recorded tantrum, and is probably gearing up to throw even longer ones, according to two American climatologists. They have also produced the strongest indication yet that human interference in the global climate is to blame. El Nino events, characterised by a warming in the eastern tropical Pacific, are driven by a combination of waning trade winds and a reversal of surface ocean currents. They produce violent storms in the eastern Pacific, and can even cause severe drought in East Africa. The latest El Nino, which ended in June 1995, lasted for five years, making it the longest over the past century. Kevin Trenberth and Timothy Hoar of the National Center for Atmospheric Research in Boulder, Colorado, suggest that it is the longest in about 2000 years. Trenberth and Hoar looked at records of a seesaw variation in atmospheric circulation and pressure called the Southern Oscillation, which is linked to El Nino. Using data from Darwin in Australia, where atmospheric pressure has been recorded since 1882, they created a simulation of the pressure fluctuations. To screen out the effects of local storms, the researchers used comparable records from Tahiti as a statistical filter. Extending the model back over the past million years, Trenberth and Hoar showed that a five-year El Nino-Southem Oscillation (ENSO) should occur only once every 1500 to 3000 vears. ENSO events have also increased in frequency since 1976, and such an extended upswing would be expected every 2000 years, they calculate. The researchers say that these variations from the norm are unlikely to be natural, and conclude that global warming is probably to blame (Geophysical Research Letters, vol 23, p 57). Nicholas Graham of the Scripps Institution of Oceanography in La Joila, California, says that the case cannot be proven by statistics. But to discount the conclusions, he says, climatologists would "And that's not very good science." - to have to invent mysterious natural cycles.
29th August 1997 El Nino causes devastation
GENEVA The big El Nino weather phenomenon brewing in the tropical Pacific Ocean is expected to be the largest climate event of the century, setting off more disasters than ever before, world climate experts predict. Scientists at a United Nations sponsored conference estimate that the El Nino developing now shows all the hallmarks of equalling or exceeding this century's strongest weather event, which hit in 1982-1983.
El Nino, which could play havoc with crops and, indirectly, with the financial markets, has become the "climate event of the century", scientists warned yesterday. The impact can be flooding or sometimes drought in California, searing droughts in Brazil, Africa and Australia, severe storms in the central Pacific and a decline in hurricanes hitting the south-eastem United States. The abnormal tropical Pacific Ocean weather pattern, which has emerged as a key factor for global investors in emerging markets from Latin America and South-east Asia, could surpass its devastating 1982-1983 episode, said weather scientists meeting in Geneva. Their message to emerging market punters was bleak: conditions not returning to normal before next summer, Australia's drought continuing, floods in Peru, more dry weather in Asia and bad news for coconut producers in Indonesia. "It's basically drought on one side of the earth and floods on the other side," said Jagadish Shukla, head of the Washington-based Institute of Global Environment and Society. Ants Leetmaa, of the Washington-based Climate Prediction Centre, added: 'The impact will be quite intense, especially in the Northem Hemisphere. "El Nino is similar to dropping a big rock in a pond the pond in this case is the Pacific Ocean." At a news conference, leading scientists attending the Conference on the World Climate Research Prograinme in Geneva urged Governments to take preemptive measures to cushion the blow of the freak weather condition El Nino on the national economies, including food output. They also warned against one of the hidden effects of El Nino the spread of diseases such as malaria is faster with mosquitoes breeding quicker in warm and wet weather. Mr Shukla said the phenomenon, which disrupts the global rainfall and wind pattems, caused record sea surface temperatures in July. Forecast models, ocean observations and satellite data showed the sea surface temperature in the eastem tropic Pacific in July had exceeded all previous records," he said. "Right now, this is already the climate event of the century," the Indian-born expert said. "We have never observed such high ocean temperatures in July in 150 years. And the only reason we say it will be the largest in 150 years is because we don't have any data from before then.' REUTERS
Oct 97 El Niño of the Century Feared
Be ready for the Worst: World Bank
WASHINGTON The powerful weather phenomenon known as El Nino could this year be the mother of all El Ninos, says the World Bank, urging countries to prepare for the worst. "This looks like it's going to be the El Nino of the century. It may well be the most major El Nino of the last 150 years.," Robert Watson, director of the bank's environment department, said during a conference in Wasmn,gton. The last big El Nino, in 1982-83, was estimated to have caused more than $US13 billion ($20 billion) in damages and lulled 2000 people worldwide. Experts believe the present El Nino phenomenon will be just as severe, bringing heavy rain and floods to parts of the world and extreme drought to other regions.
El Nino, caused by a warming in southem Pacific waters, occurs with varying strength 'every two to seven years, lasts up to 18 months and affects weather pattems across the world, causing droughts and floods in far-flung regions. Named after the Christ child because it tends to peak at Christmas, the present El Nino is already being blamed for widespread economic turmoil. The World Bank, the Inter-American Development Bank (LADB) and other multilaterals and aid agencies have responded to the crises with offers of emergency aid. Peru announced this week that the World Bank and LADB would lend the country $250 million to gear up for the harsh climate changes. Mr Watson said El Nino could undermine the gross domestic product (GDP) growth of countries that are not prepared for crop losses and flooding.
"It certainly has the potential to knock GDP growth," Mr Watson said. "Whether it will or will not have such an adverse effect on GDP will depend on whether or not there is a severe loss of rainfall, and, secondly, to what degree they [govemment officials] plan ahead." Mr Watson told the World Bank conference that global climate changes could sharply reduce crop production in Latin America and Africa. Agricultural yields in parts of Africa could drop by 30 per cent, he said. More than 80 countries already face water shortages, bank officials say, and the added strain of drought could lead to catastrophic water shortages. But with planning, some El Nino-related crises could be averted, Mr Watson said. "We can avoid the social disruption and a lot of the economic disruption if indeed we can actually use these [El Nino] forecasts." Mr Watson spoke to a conference exploring the El Nino phenomenon, the need for new curbs on greenhouse gas omissions, coral reef destruction and other envirortrnental issues. REUTERS
Winds of change New Scientist 4 Apr 98
THE mischief-making El Nino has struck again. Scientists reported last week that the unusual wind patterns caused by this year's strong El Nino have slowed the Earth's rotation very slightly, making days drag on an extra 0.4 milliseconds. El Nino, which causes a reversal of ocean currents across the Pacific, plays havoc with the world's weather. Winds near the equator that usually blow from east to west slow down, while westerly winds like the jet stream speed up. The net effect is that the atmosphere spins around the Earth faster and faster in the direction of the Earth's rotation. Scientists expected that as the atmosphere speeds up, it would steal momentum from the Earth, making the Earth spin slower and days longer. Now this effect has been measured using the Very Long Baseline Interferometer (VLBI), an array of more than 100 radio telescopes around the world. This telescope array monitors the arrival times of signals from distant quasars in the sky as the Earth rotates. By looking at the timing records, John Gipson of NASNs Goddard Space Flight Center in Maryland and his colleagues were able to measure variations in the length of day as small as five millionths of a second. Their results showed that since last summer, when a powerful El Niflo began, the day has lengthened by 0-4 milliseconds. "The changes in the Earth's rotation really give us a research tool," says David Saistein, a meteorologist at Atmospheric and Environmental Research in Cambridge, Massachusetts. "it shows the overall effect of El Nino can be felt by the entire planet." Charles Seife
LIMA Mar 98 The Trials of Life:
Sweating in a T-shirt in a sweltering open-air market, Juana de Yana cannot talk anyone into buying her thick alpaca sweaters. "Winter never came. Sales are down 80 per cent. I'm going broke," she says, surrounded by the stacks of heavyweight clothing she sells in the markets of Lima. El Nino, a giant pool of warm water that forms periodically off the Peruvian coast and alters weather patterns around the world, has brought scorching heat to Lima, damaging Peru's textile industry as people shed bulky clothing. From Guyana in the north to Chile in the south, farmers, fishermen, manufacturers and retailers have been taking it on the chin since El Nino's warm waters walloped South America!s Pacific coast. "El Nino's economic impact on South America is negative, and in some parts it is disastrous, especially the Andean countries," says Robert Gay of New York-based Bankers Trust investment bank. Across the continent, El Nino is battering economies. Its rains are washing away farm land and mudsudes are burying highways and bridges, paralysing commerce. At the opposite extreme, droughts are threatening the Brazilian rainforest and withering crops in Venezuela and Colombia.
El Nino is estimated to have cost our farmers $300 million. But, says DAVID KOOP, South America's woes are far greater. In Peru and Ecuador, which traditionally bear El Nino's brunt, more than 300 people have died and 250,000 have been driven from their homes since December because of floods and mudslides. El Nino has slowed economic growth in Peru. After a searing 7.6 per cent in 1997, the Bankers Trust says Peru will see growth this year drop to 2 per cent. In neighbouring Ecuador, the Government estimates it will cost $3.4 billion to repair damage to roads, bridges and other infrastructure. Traffic on the Pan American highway in Peru is blocked at 18 points tms week, leaving truckloads of produce to rot. " President Alberto Fujimori has ordered Navy ships to transport fruits and vegetables to circumvent the highway blockages. In Chimbote, the centre of the lucrative Peruvian fishing industry, anchovy catches have fallen from 25 million to five million tonnes a day as El Nino's warm waters drive away schools of coldwater fish.
Chile's fishing industry has also been devastated by the warm water. The economy of tiny Guyana is on the brink of disaster as rivers and streams dry up, forcing the abandonment of gold mines that are reachable only by boat. Mining officials say gold production, the backbone of the country, is expected to tumble 40 per cent this year. Drought has also struck Colombia, causing forest fires and drying up so much farmland that experts predict a 7 per cent fall in farm production this year. In Venezuela, droughts have led hydroelectric plants to ration power. And in Brazil, the worst drought in 25 years has accelerated fires that have spread to virgin sections of the Amazon rainforest. By most estimates, 10 per cent of the forest has been destroyed. But El Nino's impact is not all bad. Construction is booming as families in Peru and Ecuador rebuild houses and Governments repair highways and bridges. And in a final twist of nature, parts of the northem desert of Lima have turned green. An 80 km-long lake, dubbed La Nina, has appeared in the desert, attracting birds and wildlife. AP
JAKARTA cAug 97 - Farmers in Indonesia are worried about an extended drought which is blamed on El Nino weather pattems. Analysts fear next year's coffee crop will be ruined and the Government, may need to import the national staple crop, rice. Already the Ministry of Agriculture has provided 2 billion rupiah ($2 million) in aid to farmers whose harvests have been ruined by lack of rain. Indonesia reached self-sufficiency in rice in 1984, but, was forced to import the crop in 1994 because of drought. This year's drought is especially severe and scientists predict it may rival the El Nino drought that peaked in 1982-1983, causing $US13 billion ($20 billion) of damage worldwide. Many parts of the Indonesian archipelago, home to 200 million people, are parched brown, with former rice paddies resembling cracked moonscapes. In some fields, the only green areas are those where farmers have channelled their scarce water supplies, leaving most of the land unproductive. But the Government says there is no risk of a potential famine and rice stocks win last until March. Prices of commodities controlled by the Government - including rice and sugar - are stable, says the chairman of the National Logistics Board, Beddu Amang. But some reports claim that in Lampung, South Sumatra, up to 20,000 families are short of food and cannot afford to buy rice. Families from 43 villages in the Tulangbawang regency have been forced to eat dried cassava an alternative. One kilogram of rice in Lampung now costs 1000rp (60c), while lkg of dried cassava goes for a mere 85rp. In the Gunung Kidul, near the ancient city of Yogyakarta, many farmers have been forced to share their precious water supply with their cattle. The,drought is so severe, say villagers, that chickens are pecking at banana trees for water. At least 262 man-made lakes and deep wells have dried up in seven subdistricts in the area, reported the official news agency Antara. The Agency for Meteorology and Geophysics predicts that the dry season will not let up until December, thre months later than usual, and that when the wet season finally arrives, it will be light because of El Nino. What El Nino does is push the rain clouds over the ocean. The rain falls over the water and not on Indonesia. But the Dean of the Geography school also says "The drought will continue every year if we fail to stop deforestation and other environmental destruction".
Sept 97 The burning of South East Asia: "It seems incredible that this ecological nightmare could start in Indonesia where the rain forests are said to be richer than those in the Amazon. But the Indonesian Government has a lot to, gain from big logging companies enough to make them deaf to the pleas of environmental groups. Yet the disaster would not have happened were it not for another crucial factor. El Nino, the Weather phenomenon that has brought September rains to California and caused south-east Asia's worst drought in 50 years, delaying the rains that would douse the flames. Crucially, climatologists say, El Nino is occurring more often because of global warming. This can also be blamed on greed: of industries burning fossil fuels; of car-worshippers pumping out exhaust fumes; of Governments refusing to cut emissions. "
Over a million hectares of burning peat bogs continue to pump out as much CO2 as allof Western Europe into 1998, with repeated bouts of smog in Indonesian cities. The Rupiah plunges from 2431 to the $US down to 15,000.
Starvation in New Guinea. Crop failures caused by the failure of the seasonal rains in New Guinea have brought starvation. Sacks of rice provided by Australian airlift are described as too little. Aid workers say the airlift is welcome but cannot meet the needs of hundreds of thousands of people facing starvation.
6-9-97 Papua New Guinea is reported to be in a "desperate
as El Nino-inspired droughts and frosts push as many as one million people to the edge of starvation. Leith Anderson, the country's director-general of National Disaster and Emergency Services, said severe drought had afflicted the whole country, while in three Highland provinces severe frosts destroyed the last of the food crops. At least four people had died as a result of the frosts but the whole picture is not yet clear. Media reports in Port Moresby say 20 people have died. "It's a pretty desperate situation," Mr Anderson said by phone from Port Moresby. It was the worst drought in 50 years, with no sign of its abating. "If we do get a traditional wet season towards the end of this year the chances,are that it will be late and it will only be a short one." The worst hit areas were the Highlands provinces of Enga, Southem Highlands and Western Highlands. The chief public and severe weather forecaster, Sam Pelei, said that if the dry spell did not end by November, the nation was headed for disaster. Earlier this week the Prime Minister, Bill Skate, said 300,000 people faced starvation but Mr Anderson said yesterday that the number was closer to 400,000 and could reach one million. "We are working hard to pin down the numbers but it's a pretty desperate situation."
Nov 97 Amazon burning. Burning of the Amazon has increased up to 34% since the Rio Summit. Rain Forest burns in the Amazon basin. Unusually dry conditions caused large conflagrations that blanketed much of Brazil during this past year's fire season. In the Amazon Basin the 1997 burning season produced a "very thick" pall that extended far beyond the region where smoke has spread in recent years. Smoke may have covered half of Brazil when he was in the country in August. One reason the 1997 fires were so extensive is that forests were very dry, a consequence of El Nino, a periodic climatic oscillation, which is quite strong this year. The health effects of breathing smog from July to October each year are unknown. Physicians in the remote city of Alta Floresta in west-central Brazil concluded that half the local population was suffering from respiratory illness. In Manaus, some 600 miles northwest, there were "very significant" increases in the number of patients hospitalized with bronchitis, Artaxo notes.
Shamans cast spells to quench fires 21 March 98 BOA
As fires raged deeper into the Amazon rainforests in Brazil yesterday, Yanomami Indian shamans performed a sacred ceremony to can down the rains. In the smoke-choked village of Totobi, five elderly mystics known as 'xapuris" entered a hauucinogenic trance by snorting powdered bark of the virola tree and chanted spells to "cool the sun," said the Indian activist, Daisy Alves Francisco. 'They only gather like this in cases of big outbreaks of disease or when there are big problems with their environment." Francisco works with the non-governmental Commission for the Creation of the Yanomami Reservation. She said she had spoken with village members of the primitive Yanomami people by radio. Since January, Roraima state, on the border with Venezuela, has been ravaged by the worst fires in recent memory. There has been no rain for six months, and forecasters say the dry spell, blamed on the El Nino weather phenomenon, will last until late April. About 600,000ha of highland savannah have been burned and 5 million hectares an area larger than the Netherlands is at risk.
The fires are advancing into the rainforest, ripping through undergrowth that has lost its natural humidity in the drought. Already some 1.4 million hectares of jungle has either burned or is surrounded by fire, officials say. On Wednesday officials agreed to send about 180 experienced forest firefighters to Roraima to reinforce a similar number struggling to contain seven fire fronts in the state. But authorities failed to agree on whether to rent airborne firefighting equipment. Brazil, despite its huge forests, has no specialised water-carrying planes or helicopters.
The international environment group Friends of the Earth condemned the "lack of action" in Roraima and called for rich nations to help. "It is incredible that the world is sitting back and watching these rainforests burn," said the group's Amazon coordinator, Roberto Smeraldi. "How much worse will the situation be allowed to get before the international community acts?' Observers who flew over the Portugal-sized Yanomami Indian reservation earlier this week said a column of fire had pushed 20km into the area. REUTERS
Rains Begin To Quench Amazon Fires Associated Press
BRASILIA, Brazil (AP) -- The first heavy rains in six months fell on the remote Brazilian state of Roraima Tuesday, dampening the dried forests and kindling hopes of an end to the wildfires that have raged out of control for the past three months. The rains come a day after two Caiapo Indian shaman were flown in to the Yanomami reservation to perform a special ritual, which they believed will bring rain. "If it's a coincidence or not, I don't know, but it certainly seemed to have done the trick," said Alan Suassuna, press spokesman for the Federal Indian Bureau in Boa Vista, 1,550 miles northwest of the capital, Brasilia.
Suassuna estimated that the rains extinguished 80 percent to 90 percent of the fires. He said an accurate assessment would only be possible Wednesday, after the army, now in charge of the fire fighting operation, has overflown the area. Newly available satellite photos indicate that approximately 13,200 sq. miles, or about 15 percent of the state, has been devastated by the fires. The fires have spread into the Yanomami reservation, where one the last remaining Stone Age tribes live, and into the reservations of several other tribes. Indian reservations cover about 55 percent of Roraima state. Carlos Pereira Monteiro, head of a United Nations' team of firefighting specialists that arrived Monday, called the fires "a environmental disaster without precedent on this planet." There are currently some 1,100 men from Brazil, Venezuela and Argentina fighting the fires, the office of Roraima's governor said.
BRASILIA (April 1, 1998 09:07 a.m. EST http://www.nando.net) - Rain fell on Tuesday in various areas of Brazil's northern Amazon ravaged by huge savanna and forest fires, just hours after two Indian shamans performed an ancient ritual to bring on the storm clouds. In the town's streets, which earlier this week were shrouded in smoke, cars drove carefully through deep puddles. The two shamans, or medicine men, from the distant Kaiapo tribe celebrated in front of television cameras as the clouds opened. Flown in by the government from central Mato Grosso state, they performed a ritual on the beach of a dried-up river on Monday night, using creepers and other plants from their Xingu region to call on "the men up there" to send down rain. Officials on Tuesday flew over an area inside the massive rain forest reservation of the Yanomami Indians and reported that fires there had been completely put out by the rain.
The situation improved in other areas badly hit by fires, including
the Apiau and Caracarai farming districts, where the biggest groups
of a total of 1,700 firefighters are deployed. Fires continued
in those regions, but firefighters were finding it easier to extinguish
the flames, Fraxe said. Rain also fell on the Maraca ecological
reservation. Prized by scientists for its remarkable biological
diversity, the nature preserve has been damaged by fires. But
other affected areas, like the Pacaraima region, on the Venezuelan
border, continued dry.
Oct 97 El Niño's waves devour Rio's famous Copacabana beach. All of Rio's beaches have shrunk by 30-50 m over the past few months, but the city's most famous tourist haven has borne the brunt of the unusually high waves in recent days.
Oct 97 122 dead as killer storm hits Mexico. The resort of Acapulco devastated as Hurricane Pauline devastated the Mexican coast. Experts said the severity of the storm might have been made worse by El Niño, a weather phenomenon that warms southern Pacific waters and leads to more frequent and severe storms.
Feb 98 As many as 12 tornadoes tore through central Florida, spawned by the South-Eastern edge of an El Niño related strom system covering the south and midwest. At one mobile park a father had his baby torn from his grasp by swirling winds that reached an excess of 400 kph.
Feb 98 A resident of Laguna Beach wipes her eyes amid wreckage of a mudslide triggered by El Niño-driven rain which has destroyed dozens of houses on the Californian coast. In Florida meanwhile rescuers searched fornine peole missing after swarms of tornadoes wrought destruction, killing at least 38 people and injuring scores more.
Feb 98 Despite having areas of severe drought in Marlborough and Canterbury, New Zealand's most notable crisis attirbutable in part to El Niño is the complete breakdown of power to the central business district of the largest city, Auckland. This has been attributed to distortion and breakup of the dry ground caused by a rainless hot January as a result of El Niño and increasing demand for air-conditioners, resulting in a chain failure of all four high voltage underground cables.
Flooding in the Chinese oil fields, Bangla Desh families live on roof tops for safety.
Aug 98 Chaotic
Heavy monsoons strike Asia as part of a La Nina kickback following El Nino.
China has suffered very extreme flooding on the Yangtze delta partly as a result of excessive deforestation of the interior. A ban has been placed on logging for the first time because of the crisis, which is expected to cost $73 billion and cut GDP by 4%. Although it has had a major impact on agriculture, the floods are ironically expected to boost the industry and service sector. China's growth for the year is still expected to reach 8%.
Bangla Desh has been hit with the worst flooding ever causing production losses which amount to about $8 billion..
The US and Central America is being simultaneously hit with devastating hurricanes.
Nov 98 Hurricane Mitch devastates El Salvador Nicaragua and Honduras, killing 24,000 people after the mud slide on Casito volcano, making it the biggest killer in the region since 1780. The largest death toll of all was the Bangla Desh event of 1991.
Scientific American Mar 90
Correlations between ocean surface temperature (above) and the strength of the greenhouse effect (below) indicates a positive feedback between ocean temperature and global warming from water vapour. "The rate of increase gives compelling evidence for the positive feedback between surface temperature vater vapour and the greenhouse effect." The effects of cloud remain unknown.
Murky Water Scientific American May 90 (summary)
Scientists modelling CO2 absorbtion by the ocean place a limit of a billion tons, not the 2 or 3 supposed in absorbtion capacity of the oceans and furthermore the cycle time in the ocean may be 100 to 1000 years, much longer than the changes occurring from human impact. The picture once CO2 is absorbed is also is complicated. The usual picture is capture by plankton and subsequent dropping to the ocean floor in carbonaceous shells and fecal pellets. The effects of wind which may incerase nutrients from land to surface plankton and also assist the deposition, but this remains controversial.
Will a sea change turn up the heat? New Scientist 30 Nov 1996 Fred Pearce
GLOBAL warming could be happening much faster than climate researchers had feared, a study warns this week. Rising temperatures could reduce the ocean's ability to absorb carbon dioxide by as much as 50 per cent, leaving the greenhouse gas in the atmosphere to heat the Earth further. Until now, climate models such as those used by the intergovernmental Panel on Climate Change (IPCC) have assumed that the oceans' capacity to remove CO2 from the atmosphere will stay constant as the world warms. But George Sarmiento and Corinne Le Quere of Princeton University in New Jersey question this assumption. Their model, which predicts climate events over the next 350 years, suggests that conditions could be radically different. "This really is a startling finding," says Sarmiento. "Warmer oceans will be more stratified, causing the ocean circulation system to slow down. As a result, it will absorb much less CO2 than at present-50 per cent less in some scenarios." Each year the oceans dissolve up to 2 billion tonnes of CO2 from the atmosphere. Because of this, they help to dampen down the greenhouse effect caused by 6 billion tonnes of carbon that enter the atmosphere from fossil fuels. Scientists have long questioned whether rising temperatures would affect this disposal system, but have never before modelled the effects of change. The oceans bury CO2 by removing it from the surface layers of water. One key way of doing this is by convections currents, the biggest of which is the conveyor belt that begins in the North Atlantic.
As ice forms here, saltier-and therefore denser-water is left behind. This denser water falls to the ocean floor, drawing water in behind it and settiting up a current that begins a 1000 year journey around the world. When it returns to the North Atlantic , it contains less CO2. However, if water in the North Atlantic warms up and the current slows or carries less water, it will remove less CO2. The Princeton researchers assumed that CO2 levels would increase 1 percent a year over the first 140 years - close to the current "business as usual" scenario assumed by the IPCC. This would quadruple atmospheric concentrations of the gas. Sarmiento and LeQuere assumed atmospheric conditions would then stabilise, The Princetion models predicts that the oceans would warm by about 5 oC but that circulation would slow down dramatically. The amount of water taken to the ocean floor in the North Atlantic would shrink to less than a seventh of its former volume.
The model predicts that over 350 years, the amount of CO2 absorbed would be 49% less than assumed in current climate models As a result of positive feedback effects, global warming would increase. The researchers publish their findings in this week's Science (vol 274, p 1346). however, Sarmiento warns, much of the CO2 in the oceans is taken to the ocean floor not by the circulation system, but by organisms. Once dissolved in surface waters, CO2 is absorbed by plankton and other marine organisms. Most of this carbon eventually falls to the ocean floor. The strength of this sink for carbon depends on how inuch life the ocean is producing and is largely independent of any changes in the conveyor belt. lt is not clear, says Sarmiento, how much global warming will affect the oceans' biological productivity. His first model assumes it will remain constant, so offsetting the ocean's reduced capacity from 49% to 28% but productivity could also rise or fall. Cooler seas tend to produce more life, but iron dust from expanding deserts could make warm seas more fertile.
Little Ice Age May Affect Climate
WASHINGTON - The world may still be experiencing the effects of the 'Little Ice Age ' " which caused bitter winters and very cool summers from 1400 to 1900, scientists said yesterday. Some of the storms that lash Northernmost Europe may stem from the last gaspof the period during which the Thames froze solid over in London. Karl Kreutz and his colleagues from University of New Hampshire looked at ice cores drilled from both Antarctica and Greenland and found the atmospheric changes that marked tffis cold, dry period persisted today. This did not mean lower temperatures, but rather the timing and strength of storms off the oceans. I "Thus, increased late 20th-century storm variability may be in part a result of the continuation of these climatic fluctuations," they wrote in a report in the joumal Science, They said that although global warm- ing was almost certaiffly due to human activity, other components of weather could be the result of the lattle Ice Age changes. Dr Kreutz said his team's flndings added "another piece to the puzzle" of sorting out the effects. of global warming. - REUTERS
NOTE: Salps in particular are believed to fix CO2 by forming heavy pellets of excrement which fall to the ocean floor and could respond to warming.
Trends of solar activity and cloud cover suggest solar activity may have a moderating effect on global warming NS11 Jul 98 48
NS 11 Jul 98 46
OUR WORLD is ruled by the Sun. its life-giving energy warms the Earth, fuels our crops and drives the weather. This much we can take for granted. But now signs are emerging that the Sun has a more subtle influence, too, which arises from regular changes in its activity. Variations in the amount of energy streaming our way seem to influence the climate in myriad ways. But there is a puzzle here. During these fluctuations, which typically vary over an 11-year cycle, the energy emitted changes by a tiny 0.1 per cent. From cycle to cycle, the differences are even smaller. Yet evidence is mounting that these minuscule variations lead to measurable changes in climate around the world. "It is not clear how such small changes can be responsible for the fluctuations in climate," says Joanna Haigh, an atmospheric physicist at Imperial College, London. Something must be amplifying the small variation in energy coming from the Sun, but what? And perhaps more importantly, by how much?' Global average temperatures have risen by around 0.6 'C until recently human over the past century, and human activity has been fingered as the main culprit. But now a few climatologists have begun to suggest that the Sun's influence could be much greater-big enough to swamp that of greenhouse gases and let human polluters off the hook. This led the British journalist Nigel Calder to conclude in his book The Manic Sun, published last year, that there is "little scope for any contribution [to the recent warming] from greenhouse warming'. Or, as The Observer newspaper put it in April, humans are not to blame" for global warming. So is this hype, mischief-making or the climate breakthrough of the decade? Scientists have been looking for a link between climate and changes in the Sun for more than 200 years. The latest claim has its origin in a paper published in 1991 by Eigil Friis-Christensen and Knud Lassen of the Danish Meteorology Institute in which they compared solar activity and global temperatures over the past 250 years. The researchers uncovered a striking correlation over the past century between rising temperatures and the length of the solar cycle. This has been steadily decreasing and is now several months shorter than it was at the end of the 19th century Astrophysicists agree that shorter solar cycles imply more solar activity, which in turn means that more solar radiation reaches the Earth. The conclusion seemed inescapable: changes in the Sun were causing warmina on Earth. However, there were some concerns about a graph Friis-Christensen and Lassen used, which compared temperature with the length of the solar cycle. Most scientists do not use the length of the solar cycle as an indicator of the Sun's activity. A plot in the same paper comparing temperature with the number of sunspots was far less successful, especially for the period since 1940. While the solar cvcle length has followed the temperature-dropping in mid-century and then rising again as temperatures have hit new records-the trend in sunspot numbers has been downward since 1960.
Nevertheless, Friis-Christensen and Lassen's work caused a flurry of concern among greenhouse scientists in the runup to the Earth Summit of 1992, when the world's governments called for action to cut emissions of greenhouse gases. That year Tom Wigley, then of the Climatic Research Unit at the University of East Anglia, and his colleague Mick Kelly tried to work out how much of the world's warming was due to a more active Sun, and how much to greenhouse effects. Using computer models, the researchers looked at what happened when they gave various weightings to the effects of solar activity and greenhouse gases. They found that they obtained the best match with global temperatures recorded over the past 200 years when 100 per cent of the change was attributed to the Sun, and none to the greenhouse gases. But the match was almost as good for the same period if they ignored solar changes altogether and just considered the greenhouse effects. For both these results they had to make assumptions about the strength of these effects which few scientists would consider reasonable. Ilf they kept to more realistic levels of amplification, they found that greenhouse gases explained most of the recent warming. Undeterred, Friis-Christensen returned to the frav last summer, along with Henrik Svensmark, also from the Danish Meteorological Institute. This time, they had a mechanism to explain whv tiny changes in the Sun could have big effects on Earth. It was all down to an intriguing correlation thev spotted between cloud cover in the tropics and the number of small but verv energetic particles called cosmic rays reaching the Earth from deep space. To explain this correlation, the two researchers revived an idea proposed 20 years ago that cosmic rays may encourage clouds to form in the Earth's atmosphere. More cloud might reflect more of the Sun's energy back into space, leading to a cooler world. The link between cosmic rays and solar activity is the solar wind, the charged particles streaming from the Sun. The solar wind is known to push cosmic rays aside, preventing them from from bombarding the Earth. So the more active the Sun is, the stronger the solar wind, leading to fewer cosmic rays and a drop in the cloud cover. Result: global warming. Or so the reasoning goes. The Danish team's new graph certainlv suggests a link between solar activity cosmic rays and cloud cover. Satellite data show changes of 3 to 4 per cent in average cloud cover over the tropics from 1980 to 1995, in step with monthlv figures for the intensity of cosmic rays arriving at the Earth (see Diagram). Intriguing as this correlation is, it is far from proof that solar activity and cloud cover are connected. Friis-Christensen and Lassen used data for cosmic ravs cox-ering only 15 years, which is not en-en oneand-a-half solar cycles, and their figures for cloud cover spanned only seven years. Such a short time period makes it hard to rule out the possibility that the correlation is simply a matter of chance, and that something else caused the cloud changes. For instance, climate scientist Keith Shine from the University of Reading points out that the cloud data begin shortly after one major volcanic eruption, from El Chich6n in Mexico, anci end just before another, Pinatubo in the Philippines. Both eruptions poured lar-e amounts of debris into the upper atmosphere and had a worldwide impact on climate. To add to the confusion, the peak period of cloud cover, in 1987, also coincided with a strong El Nifio e\-ent. This redistribution of warm water in the tropical Pacific Ocean is the largest natural perturbation of the tropical climate. Researchers from Caltech are about to publish a paper showing that the data on cloud cover in the 1980s correlate as well with El Nino as they do with cosmic rays.
Clouding the issue
In last year's paper, Friis-Christensen also attempted to extend his data for cloud cover back to 1975, and forwards to 1995. He found that the correlation with cosmic rays remained, while the correlation with the other sources like El Niho decreased drastically. However, critics point out that the extra data are from three separate satellite sources and relate only to oceans in the southern hemisphere. Friis-Christensen himself admits that "a detailed comparison of absolute levels is difficult". There are other uncertainties ivith the cosmic ray theory, not least the fact that no one knows exactly why, these particles from space should affect the Earth s cloud cover at all. There are ,several competing ideas Christensen and Larsen suggest that cosmic rays create an electrical charge in tiny particles in the atmosphere that act as nuclei for the formation of cloud droplets. The charge would make the particles much more effective at seeding clouds. Brian Tinsley, a British researcher now working at the University of Texas in Dallas, has an alternative idea. He believes that electric fields caused by cosmic rays could encourage water droplets to freeze. These would then act as nuclei for the formation of cloud droplets. Whether either of these mechanisms would create enough cloud to affect the climate remains to be seen. "We don't know whether the effect is large enough," says Friis-Christensen. Even assuming that cosmic rays do produce clouds, it is not certain whether they would actually cool the world. Clouds at low altitude do tend to reflect more sunlight, and so have a cooling effect. But higher-altitude clouds generally have the opposite effect, trapping heat and warming the atmosphere. Jasper Kirkby and Frank Close of CERN, the European Laboratory for Particle Physics in Switzerland, hope to perform experiments that will answer at least some of these questions. Their idea is to re-create the conditions of the upper atmosphere in a cloud chamber-a piece of kit conunon in particle physics labs. They would fill the chamber with mixtures of gases and cloud-forming nuclei characteristic of different heights in the atmosphere and then blast them with CERN particle beams, which stand in for cosmic rays. By seeing whether clouds form, and if so what kind and by what mechanism, they hope to provide data for climatologists to plug into their global climate models. Ultimately Kirkby believes the experiment could tell us how important a contribution cosmic rays have made to global warming in the past century.
It is still early days. "This is not even an official proposal to CERN yet. It is just an idea," says Kirkby. Friis-Christensen believes their experiment could work. But Giles Harrison, a leading expert on atmospheric electricity from the University of Reading, doubts whether cloud chamber experiments will ever clinch the argument. "It would be hard to generate microphysical properties genuinely typical of the atmospheric conditions before a cloud forms." One problem, he says, is the massive variability of electrical conditions in the atmosphere, even in a clear sky. Harrison plans his own experiments using weather balloons. Jasper Kirkby agrees that measurements in the real atmosphere are important, he points to the greater control that is possible with cloud chamber experiments. "We hope to be able to switch things on and off to see what happens. Do clouds form and disappear?" he says. And he insists that the experiment will be able to model the atmosphere effectively. "It is just air and water vapour and aerosols." Some greenhouse scientists are angered by all this interest in solar forces. They know that industry lobbyists are keen to promote ideas of this kind, as a way of blocking action to limit emissions of known greenhouse gases. And while Shine says the solar work is interesting and worth pursuing he, too, despairs at -commentators who leap from conjecture to conclusion without waiting for research to confirm or refute them. And he insists that whatever the effect on global climate of changes in the Sun's activity, it does not undermine the role of greenhouse gases. The greenhouse effect is "hard, repeatable science", he says. "We know that human activity has increased the concentrations of these molecules and has enhanced the greenhouse effect." Most solar scientists side with Shine. Even Friis-Christensen does not insist that his proposed cosmic ray effect is the only force for global climate change. "I cannot claim that our ideas disprove the greenhouse theory," he says. "Both mechanisms may work together. Greenhouse gases could have played a significant role." Kirkby agrees: "There is certainly a greenhouse effect," he says. "The question is whether it is responsible for all the 0.6 OC warming in the past century, or two-thirds or a fifth-or what?" Tinsley thinks a slow increase in solar activity was largely to blame for the 0.3 'C rise in global temperatures between 1890 and 1970. But he says the further 0.3 'C warming since then must have been caused by something else. "There are good theoretical reasons for expecting greenhouse gas effects to become obvious in the early 21st century," he warns. Wigley, now at the National Center for Atmospheric Research in Boulder, Colorado, has also been refining his estimates of the relative contributions of the two effects. His latest computer model suggests that the solar influence on global warming between 1890 and 1997 was 20 to 40 per cent. He says his models can re-create the rapid warming between 1910 and 1940, the levelling off until the end of the 1960s, and the warming since then, but only by including solar effects. It seems a new consensus could be emerging. The influence of the Sun and of greenhouse gases marching hand in hand appears to account for the past century's slow rise in global temperature. But greenhouse gases could well continue to dominate-unless the Sun has more surprises in store.
Send in the Clouds (extract) NS 30 May 98 29
MICROBES make the weather. It sounds bizarre, bilt biologists have known for vears that marine plankton can create clouds. If this were just a meaningless side effect of their existence the storv would end there. But suppose microbes are in fact orchestrating the elements. Suppose there is a link between their survival and climate control. What if these specks of life were using clouds, wind and rain to carrv themselves around the planet like a global taxi service? It is tempting to dismiss these ideas out of hand, but consider their pedigree. Bill Hamilton from the University of Oxford is renowned for his work on social and sexual evolution and has a knack of being ahead of the field. He was thinking about selfish genes long before Richard Dawkins popularised the notion. Now workin" with Tim Lenton, a young atmospheric chemist from the University of East Anglia, Hamilton has come up with an astounding idea. By explaining why microbes produce clouds he has also formulated the first biologically credible mechanism for Gala-the theory that Earth acts like a superorganism, with all its biological and physical systems cooperating to keep it healthy.
It is more than a decade since a group of scientists led by geophysicist James Lovelock published a paper stating that marine algae are part of a massive global regulatory system that keeps the climate stable. Most produce a gas called dimethyl sulphide (DMS), which reacts with oxygen in air above the sea to form tiny solid particles. These sulphate aerosols provide a surface on which water vapour can condense to form clouds. And clouds keep the planet cool by reflecting solar radiation back into space. Lovelock, who proposed the Gaia hypothesis in 1972, argues that this process could create a self-regulating global thermostat. Warmer conditions increase algal activity and DMS output, seeding more clouds, which block out the Sun. Then, as the climate cools, algal activity and DNIS levels decrease and the cycle continues. "The DMS paper went down very well," says Lovelock, "but biologists were not satisfied. They opposed Gaia because they could not see how organisms had evolved to behave in a way that regulates the planet." Natural selection works at the level of the individual, weeding out those that are poorly adapted to their particular lifestyle by dint of their genes. So possessing the genetic machinery to produce DMS must benefit individual microbes. But how can individuals working for their own selfish ends have evolved to influence the global environment?
Good for algae, good for Earth
Lovelock points out that DMS production benefits both the organism and the planet as a whole. "Without organisms doing their thing the Earth would be a much warmer place," he says. Peter Liss and Andrew Watson, environmental scientists from the University of East Anglia, have recently suggested that algal DMS production cools the planet by 4'C. As well as being good for the Earth, cooling is good for algae, because if the oceans get too hot, the warm upper layers become separated from the cooler depths and algae at the surface are cut off from sources of nutrients below. Algae may also benefit from nitrogen raining dovn from the clouds they have helped to form. Such arguments did not convince Hamilton. He became intrigued by Gaia through chatting to Lovelock. "I was particularly interested in algal production of DMS, because it is so hard to find an evolutionary explanation-the effect on the algae themselves is so remote," he says Lovelock introduced Hamilton to Lenton, whose research into the control of nutrient ratios in the ocean had convinced him that natural selection working on individuals can have large-scale environmental effects. If Hamilton and Lenton could only discover why algae produce DMS they might be able to make the jump from local to global. The immediate biological function of DMS is not clear. Its precursor, a chemical called dimethylsulphoniopropionate (DMSP), is thought to protect algal cells from the drying effects of the strong salt solution in which they live. But the algae carry an enzyme that breaks down DMSP into DMS and acrylic acid. One theory is that toxic acrylic acid is released to deter predators when cells are damaged. In this scenario DMS is just a waste product. Algae do seem to release greater quantities of DMS when attacked by other plankton or even by viruses. "The deterrent works well on a laboratory scale," says Gill Malin, a marine microbiologist at the University of East Anglia, "but the natural ocean environment is very different. And the hypothesis does not explain whv some algae release low levels of DMS ;ll the time." The idea that algae might produce DMS to get themselves into the air occurred to Hamilton first. "Tim had mentioned that DMSP has a possible function as an antifreeze," he recalls. "Now why would a cell in a tropical ocean need antifreeze? Perhaps they sometimes end up high in the air, shot up there by a waterspout. Or maybe there are other ways they could go. Convective energy created by cloud formation would help them." Flying high, the algae would be exposed to very low temperatures. Idle speculation rapidly led to the formation of a theory that beautifully explains lvhv algae produce DMS. "Seldom have I had a run of reading where so many papers were relevant or connected and nothing contradicted my ideas," savs Hamilton. "I felt certain that there was something interesting here." If algae were using the atmosphere as a route for global dispersal then any adaptation that helped them on the way would have strong evolutionary benefits. "Dispersal is the third priority for an organism, after survival and reproduction," says Lenton. Indeed, it is more than tnvo decades since Hamilton and biologist Robert May devised a model highlighting the importance of dispersal. The benefits of successfully colonising a new area are so great, they concluded, that organisms will evolve to send their progeny away from home even if they never end up in a better place. "The crucial thing," Hamilton points out, "is that this mechanism only has to confer a very tiny advantage to make it likely to have evolved. Some of these marine algae have been evolving for at least 600 million years." Hitching a ride on thermals and air currents is a highly efficient way of getting around the planet. So it is hardly surprising that air is teeming with microbes. Ten thousand particles per cubic metre of air is quite normal near the ground, and live bacteria and fungal spores have even been found 50 kilometres up in the atmosphere. In 1993, William Marshall, an aerobiologist working for the British Antarctic Survey, cultured organisms, including algae arriving at the Antarctic, in an air mass that had travelled 1500 kilometres from South America. "This was the first time intercontinental aerial dispersal of anything had actually been recorded," savs Marshall. "They must have gone up very high in the atmosphere." .... continued