There is no doubt that we should take solar radiation into account. We have seen ground temperatures rising since 1975, and it is important to know to what extent that has been caused by the sun or by carbon dioxide.

Think on a 50-year scale, which is a much more natural time-scale for global warming. The US is right now spending about 200 million dollars annually on research into renewable energy.

Even if I was a bad right wing guy, to the extent of whether my arguments are right or wrong, they're right or wrong independently if I'm right or left.

The obvious issue is providing clean drinking water and sanitation to every single human being on earth at the cost of little more than one year of the Kyoto treaty.

So it's mainly a question of helping the Third World overcome the effects of global warming.

Just because there is a problem doesn't mean that we have to solve it, if the cure is going to be more expensive than the original ailment.

The fact that we're catching more fish per person than we've ever done before doesn't mean that there are not particular places where we've managed fisheries badly.

My suggestion is that we should first work to ensure the Third World has clean drinking water and sanitation.

Obviously any group that has to have funding also needs to get attention to their issues.

On average, global warming is not going to harm the developing world.

When a business group tells us there is nothing wrong with the environment, naturally they may have good arguments, but we are also sceptical, because we know that they have an interest in these things.

The second thing is, if you want to do something about global warming, you have to think much more long-term. There is something wrong with saying we should start using renewables now, while they are still incredibly expensive.

There is no doubt that we should take solar radiation into account. We have seen ground temperatures rising since 1975, and it is important to know to what extent that has been caused by the sun or by carbon dioxide.

I really try to say things as they basically are and it so happens that it is a good message that things are getting better, but there are still problems.

Of course, the world is full of problems. But on the other hand it's important to get the sense... are we generally moving in the right direction or the wrong direction?

But this is an occupational hazard of being a scientist. You say this is the best information I have and then you realize that not everyone is going to read the footnotes or the whole book, so people are going to get the wrong impression.

It seems incontrovertible to me that there is a global warming effect and that it is going to be serious, probably not in the amount of, say, six degrees warming, but it's likely that we'll get two to three degrees warming and that will be serious enough.

The Kyoto treaty has an estimated cost of between US$150 and $350 billion a year, starting in 2010.

A review was published in Nature, very scathing, essentially calling me incompetent, though they didn't use that word. I am putting a reply on my Web site in a few days, where I go through their arguments, paragraph by paragraph.

We have to be aware that the scientific community throws up tons of different hypotheses and at a certain point we'll find out who was right and who was wrong. But we have to go with the best information right now, which I would claim to be the IPCC reports.

I think it's great that we have organisations like Greenpeace. In a pluralistic society, we want to have people who point out all the problems that the Earth could encounter. But we need to understand that they are not presenting a full and rounded view.

Even if every major government were to slap huge taxes on carbon fuels - which is not going to happen - it wouldn't do much to halt climate change any time soon. What it would do is cost us hundreds of billions - if not trillions - of dollars, because alternative energy technologies are not yet ready to take up the slack.

Global warming is real - it is man-made and it is an important problem. But it is not the end of the world.

I tentatively believe in a god. I was brought up in a fairly religious home. I think the world is compatible with reincarnation, karma, all that stuff.

In the rich world, the environmental situation has improved dramatically. In the United States, the most important environmental indicator, particulate air pollution, has been cut by more than half since 1955, rivers and coastal waters have dramatically improved, and forests are increasing.

Listen, global warming is a real problem, but it' s not the end of the world. A 30-centimetre sea level rise is just not going to bring the world to a standstill, just like it didn't over the last 150 years.

Money spent on carbon cuts is money we can't use for effective investments in food aid, micronutrients, HIV/AIDS prevention, health and education infrastructure, and clean water and sanitation.

The main environmental challenge of the 21st century is poverty. When you don't know where your next meal is coming from, it's hard to consider the environment 100 years down the line.

The only thing that will really change global warming in the long run is if we radically increase the speed with which we get alternative technologies to deal with climate change.

The saddest fact of climate change - and the chief reason we should be concerned about finding a proper response - is that the countries it will hit hardest are already among the poorest and most long-suffering.

There is no question that global warming will have a significant impact on already existing problems such as malaria, malnutrition, and water shortages. But this doesn't mean the best way to solve them is to cut carbon emissions.

To prepare adequately for the challenge of global warming, we must acknowledge both the good and the bad that it will bring. If our starting point is to prove that Armageddon is on its way, we will not consider all of the evidence, and will not identify the smartest policy choices.

We need to invest dramatically in green energy, making solar panels so cheap that everybody wants them. Nobody wanted to buy a computer in 1950, but once they got cheap, everyone bought them.

We worry about the seemingly ever-increasing number of natural catastrophes. Yet this is mainly a consequence of CNN - we see many more, but the number is roughly constant, and we manage to deal much better with them over time. Globally, the death rate from catastrophes has dropped about fifty-fold over the past century.

When thinking about the future, it is fashionable to be pessimistic. Yet the evidence unequivocally belies such pessimism. Over the past centuries, humanity's lot has improved dramatically - in the developed world, where it is rather obvious, but also in the developing world, where life expectancy has more than doubled in the past 100 years.

Wishful thinking is not sound public policy.

There is no rational reason to doubt that the universe has existed indefinitely, for an infinite time. It is only myth that attempts to say how the universe came to be, either four thousand or twenty billion years ago.

When in doubt wear red.

As I think through the issue of funding the rebuilding of Iraq, I think about the analogy of a bankruptcy proceeding. There is no doubt that Iraq as a country is bankrupt.

After having dispatched a meal, I went ashore, and found no habitation save a single house, and that without an occupant; we had no doubt that the people had fled in terror at our approach, as the house was completely furnished.

If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.

We criticize, copy, patronize, idolize and insult but we never doubt that the U.S. has a unique position in the history of human hopes.

If you've got talent, stick with it... because talent wins out, without a doubt.

That a great battle must soon be fought no one could doubt; but, in the apparent and perhaps real absence of plan on the part of Lee, it was impossible to foretell the precise scene of the encounter.

I would not be gotten into a schoolhouse until I was eight years old. Nor did I accomplish much after I started. I doubt if I had gone to school six months in all when my father died. I was fourteen at the time.

No doubt Western civilization has in the past been full of wars and revolutions, and the national elements in our culture, even when they were ignored, always provided an unconscious driving force of passion and aggressive self-assertion.

You have to not listen to the nay sayers because there will be many and often they'll be much more qualified than you and cause you to sort of doubt yourself.

It has since been agreed that speeches given in English will be translated into French and vice versa, and even into German and Italian when necessary. No doubt translations into Esperanto will also soon be in demand.

Who has suffered? The families of the dead, no doubt. But a greater loss was inflicted on Pakistan because, as I said, we lost the pillars of our society.