Letters: Global warming

How seawater in the sky could halt global warming

Sir: The ingenious global warming mitigation idea proposed by the Nobel laureate Professor Paul Crutzen and described in the excellent article by Steve Connor (31 July) may well offer a solution to the uniquely important and urgent question of global warming. It should undoubtedly be explored further.

Another such geo-engineering idea is currently being examined in conjunction with my collaborators Professor Tom Choularton, University of Manchester, Professor Stephen Salter, University of Edinburgh and Professor Mike Smith, University of Leeds, and their colleagues. It involves - as does the Crutzen proposal - increasing the reflectivity (albedo) of the Earth to incoming sunlight. Obviously, if a greater fraction of the sunlight arriving at the top of the atmosphere is reflected back into space, the overall result is a cooling of the Earth. This cooling could be achieved, in principle, by increasing the reflectivity of low-level shallow maritime clouds - which cover a large fraction of the oceanic surface - by atomising sea-water to produce tiny droplets which enter the clouds and for well-established physical reasons cause them to become more reflective.

Computations made using the Meteorological Office's global climate model show that the scheme could produce a global cooling - sufficient to balance the warming resulting from a doubling of the atmospheric carbon dioxide concentration - by seeding clouds in three oceanic regions which together cover about 3 per cent of the Earth's surface. Plans are well advanced for dealing with the crucial engineering problems of the production and dissemination of these seawater droplets at the rates and on the geographical scales required. To date, we have published three papers on this work in the open scientific literature.

This proposed technique has the advantages that the only raw material required is seawater, the amount of global cooling could be controlled and if necessary the system could be switched off with conditions returning to normal within a few days. However, as with the Crutzen plan, there are a number of important possible meteorological and safety ramifications which must be fully and satisfactorily examined before operational deployment of such a scheme would be justified.

We agree entirely with Professor Crutzen that the ideal solution would be for fossil fuel burning to be reduced by the requisite amount to halt the global warming, and that such a reduction is highly unlikely to occur in the near future. These geo-engineering techniques offer the possibility that we could buy time within which we could stave off catastrophic warming while carbon dioxide levels are being reduced to acceptable levels. It is deplorable that resources have so far not been provided to enable these ideas to be adequately examined.

JOHN LATHAM

NATIONAL CENTER FOR ATMOSPHERIC RESEARCH, BOULDER, COLORADO, USA

Big powers have let Middle East down

Sir: It's so easy to cloak the sixty years of inadequacies of the UN's five permanent members (P5) in the organisation's mantle and blame it for their failures. Your front page headline "While the UN fiddles, the Middle East burns" (7 August) does just that.

You should aim your fire at the P5. As the wartime Great Powers, they secured agreement from smaller states that they alone merited the extraordinary power of the veto. Let them show again that same leadership and capacity for partnership which, alas, is lacking in their timid draft Security Council Resolution.

Currently, their leadership in the field for the UN is poor. In June 2006, their UN troop contributions totalled a paltry 2,230 (China 1,408, France 400, Russia 121, UK 289 (283 in Cyprus), US 12). These figures would appal their leaders of 1945 who saw Chapter VII of the UN Charter, which addresses threats to the peace and acts of aggression, as a blunt warning to all that they would not hesitate to wield the stick themselves if needed.

The announcement of a UN-mandated force, to be led by a P5 member with troop contributions from the other four and charged to assist Lebanon address clauses 2, 3 and 4 of Security Council Resolution 1559 would give evidence of their intent. It would not stop the fighting today but it would bring about its end sooner. Let those who argue that this will induce mission creep deny the P5 have been mired in this dispute since 1948, when their squabbling contributed to the assassination of Count Bernadotte, then UN Middle East mediator. The standing of this Gang of Five, still gripping tightly their veto power, will continue to fall and in its descent, may take down with them the UN itself which your misleading front page wrongly blames. In the name of "We, the peoples", we urge these five states to prepare for deployment now.

DAVID WARDROP

STRATEGIES FOR PEACE LONDON SW6

Sir: Your headline tells us that the "UN fiddles while the Middle East burns". Please do not join the insidious drip-feed of politically-motivated doubt that is undermining the authority of UN. The delay is due to the intransigence of Israel and Hizbollah and their various backers, not the UN itself, which has the unwelcome but necessary task of providing the forum for this debate of the deaf.

RICHARD LAWSON

CONGRESBURY, SOMERSET

Sir: The proposed moves to insert an international peace-keeping force in southern Lebanon and to provide help for Lebanon to rebuild seem inappropriate. Quite why a peace-keeping force should be stationed in south Lebanon rather than in north Israel is hard to understand. UN experience is that it has much more to fear from Israel than Hizbollah. And that the international community should be called on to make good the terrible injuries to Palestinians and Lebanese and their infrastucture is inexplicable.

WADE MANSELL

CANTERBURY

Cubans better off than American poor

Sir: Rupert Cornwell, writing from Washington (3 August), perhaps does not know that many families there would appreciate the benefits that the democratically elected Fidel Castro and colleagues have brought to Cuba.

Infant mortality in Washington is higher than in Cuba, whose health indices, which Cornwall does not cite, are second only to Canada in the Americas. Poor families in the US would also appreciate the free and universal coverage of the Cuban health service and free education at all ages. Cubans do have low personal incomes (as do millions of people in the Americas), but they benefit from a high social wage.

It is indeed unfortunate that sustained aggression from the US means that expenditure on the military has to be high, but thanks to Raul Castro's leadership of defence, the country will not easily fall like a "ripe fruit" (the words are from one US president, Andrew Jackson) to the US.

MARK BURTON

MANCHESTER

Sir: Castro has been in power for so long that it is easy to forgot that before his arrival Cuba was virtually an off-shore safe haven for the Mafia, where the majority of the population were impoverished and uneducated and had very little health care and the government was run by rich, respectable gangsters.

Since Castro took over, the population may still be poor, but they do have education and a health service. That is a gain on two out of three. If they are now run by a communist, he cannot be worse than the Mafia, can he? When he goes, will the "international community" turn a blind eye if the mafia move in again?

DAVID FOSTER

IPSWICH

Sir: In the Fidel Castro debate, Glynn Naughton (letter, 3 August) is wrong in stating that democracy has "seen off" nine US presidents. It is only eight - the assassin's bullet accounted for the ninth.

MICHAEL G COTTRELL

MARLOW, BUCKINGHAMSHIRE

Sir: Martin Arundell, in his glowing account of the wonderful humanitarian work Cuban doctors have done around the world (letter, 5 August) forgot to add, "when they were needed at home".

PHILIP MORAN

LONDON N11

Treatment based on evidence

Sir: Rather than assuming that American research on medical flaws applies to the UK, Jeremy Laurance should have focused on the work that is taking place in this country to ensure that patients receive treatment that has good clinical evidence behind it ("The medical flaws that should make doctors blush", 3 August).

The new GP contract has scored a world first by linking quality of care to practice resources. This is done via the national Quality and Outcomes Framework (QOF). The QOF ensures that patients, including those suffering from diabetes, heart disease and high blood pressure, receive treatment that is steeped in good clinical evidence. Independent research shows that, in the case of hypertension alone, almost 9,000 patients in England will be saved from potentially life threatening heart and stroke problems in the next five years as result of GPs' success in delivering the QOF.

Statistics and, moreover health policies, imported from the USA, do not necessarily have relevance in the UK, a lesson which our politicians would do well to learn

DR HAMISH MELDRUM

CHAIRMAN, GPS COMMITTEE, BRITISH MEDICAL ASSOCIATION, LONDON WC1

The City is no place for cry-babies

Sir: Thank you, Helen Green, for yet another kick in the teeth for women trying to make it in the City. Her win against Deutsche Bank ("City worker wins £800,000 over bullying", 2 August) may have left her £828K better off, but it has lumbered the rest of us with the additional task of proving to already nervous City employers that we're not just gold-digging cry-babies.

The antics to which Green was subjected (shouts of "you stink", raspberry-blowing, staring) are what most of us would term harmless office banter. For any other Greens out there, let me offer some advice: when they plant a whoopee cushion under your chair, when they comment on your breasts, when they turn your monitor upside down, don't run into the ladies' and cry. Deal with it.

POLLY COURTNEY

LONDON NW2

Sir: I have worked I the City for the past five years as an occupational health nurse and have worked for outsourced healthcare companies. In my experience, doctors and account managers from outsourced healthcare companies will write what ever they are told to by the human resources (HR) departments. It is about keeping the client "happy".

Stress brought on by workplace bullying in investment banks is common and well-known in the industry. But the HR departments do not want documented evidence, so as to prevent personal injury claims by disgruntled employees. Large investment banks are known to offer out-of-court settlements to avoid grievances that can lead to employment tribunals.

What is astounding is how some occupational health companies treat their own staff. These companies are so busy pleasing the banks that they forget that we have our own stress due to heavy workload and unrealistic demands placed on us by the account managers.

CHRISTINE HOSEIN

LONDON N19

Terrorised by gangs of violent sparrows

Sir: Many sparrows infest my lovingly tended kitchen garden ("The secret life of sparrows", 2 August). The lettuce row went first, within an hour of the first shoots pushing through. Likewise the spinach. They helped each other under the spinach netting to tear the young leaves. This morning I watch gangs of them tearing the blossom off the runner beans. They frighten the blackbird Arkwright when it tries to take a bath in the water dish put out to help it through the heatwave. They frighten the collie Spike as he tries to snooze in the shade. If you want to keep burglars out of your city houses, hire my sparrows.

PETER DUNN

BRIDPORT, DORSET

Historic computer

Sir: Julia Pierce ("Rotten?", 3 August) claims that when she switches on her Apple Mac, she sees a "smiling face". Either she has never used a Mac, or is using an operating system that was retired in the late 1990s. When you switch on a Mac, you now see - an apple. She should try upgrading.

TIMOTHY MORTON

LONDON SW15

Rework of art

Sir: The artist Peter Alexander is distraught because some one broke his "artistic" piece of black plastic ("Pompidou Centre wrecks art on loan from US", 4 August). He need not worry. Any competent plastics engineer could knock him up another one for a few hundred quid. We were given the length and height but would need to know the thickness.

R C M WATSON

LEIGH ON SEA, ESSEX

Genetic heritage

Sir: There are precedents for the importation of Danish sperm to northern England (report, 5 August), and for the birth there of many blue-eyed blond children. It is generally known as the Viking settlement. I am sure today's sperm will feel quite at home.

EDWARD JAMES

PROFESSOR OF MEDIEVAL HISTORY, UNIVERSITY COLLEGE DUBLIN

Continental children

Sir: I believe that David Mc-Kaigue gives the wrong impression when he states (letter, 5 August) that on the Continent formal education often begins at seven years of age and that the children thereby progress better and are happier than our own. Apart from other factors involved, he omits to mention that on the Continent the system of nursery education is generally far superior to our own.

W H COUSINS

UPMINSTER, ESSEX

Bags of concern

Sir: Tesco are good at publicity for their "save plastic bags" initiative. You should notice that in the same week, Boots (in Chichester, anyway) has quietly and equally laudably put up notices saying, "Need a bag? If you can manage without one, you can help save the environment." Other stores, please copy, especially M&S, whose assistants just grab a bag for every new customer at the tills for "5 items or less" (they mean "fewer", of course, but are no good at English or eco-care).

MIKE STONE

CHICHESTER, WEST SUSSEX

Clever sheep

Sir: Here on Exmoor we regularly see sheep crossing cattle grids on tiptoes. Very elegant. (Letters, 1 August.)

PETER WHITBY

PORLOCK, SOMERSET