[O]ur long-term security is threatened by a problem at least as dangerous as chemical, nuclear or biological weapons, or indeed international terrorism: human-induced climate change. … The impacts of global warming are such that I have no hesitation in describing it as a “weapon of mass destruction.” Like terrorism, this weapon knows no boundaries. It can strike anywhere, in any form…

Asian Homo erectus died without issue and does not enter our immediate ancestry (for we evolved from African populations); Neanderthal people were collateral cousins, perhaps already living in Europe while we emerged in Africa... In other words, we are an improbable and fragile entity, fortunately successful after precarious beginnings as a small population in Africa, not the predictable end result of a global tendency. We are a thing, an item of history, not an embodiment of general principles.

At least once per year, some group of scientists will become very excited and announce that:
•The universe is even bigger than they thought!
•There are even more subatomic particles than they thought!
•Whatever they announced last year about global warming is wrong.

Enthusiasm for the global-warming scare also ensures that heatwaves make headlines, while contrary symptoms, such as this winter’s billion-dollar loss of Californian crops to unusual frost, are relegated to the business pages. The early arrival of migrant birds in spring provides colourful evidence for a recent warming of the northern lands. But did anyone tell you that in east Antarctica the Adélie penguins and Cape petrels are turning up at their spring nesting sites around nine days later than they did 50 years ago? While sea-ice has diminished in the Arctic since 1978, it has grown by 8% in the Southern Ocean.

Entropy theory is indeed a first attempt to deal with global form; but it has not been dealing with structure. All it says is that a large sum of elements may have properties not found in a smaller sample of them.

Global nuclear war could have a major impact on climate—manifested by significant surface darkening over many weeks, subfreezing land temperatures persisting for up to several months, large perturbations in global circulation patterns, and dramatic changes in local weather and precipitation rates—a harsh “nuclear winter” in any season. [Co-author with Carl Sagan]

I think that the unity we can seek lies really in two things. One is that the knowledge which comes to us at such a terrifyingly, inhumanly rapid rate has some order in it. We are allowed to forget a great deal, as well as to learn. This order is never adequate. The mass of ununderstood things, which cannot be summarized, or wholly ordered, always grows greater; but a great deal does get understood.
The second is simply this: we can have each other to dinner. We ourselves, and with each other by our converse, can create, not an architecture of global scope, but an immense, intricate network of intimacy, illumination, and understanding. Everything cannot be connected with everything in the world we live in. Everything can be connected with anything.

If the potential of modern science is to be realized, there is no alternative to global public goods and institutions.

If we continue on our current course, the damage that has been the defining feature of my lifetime will be eclipsed by the damage coming in the next. … Science predicts that were I born today, I would be witness to the 2030s—The Amazon Rainforest, cut down until it can no longer produce enough moisture, degrades into a dry savannah, bringing catastrophic species loss—and altering the global water cycle.

In fact, the thickness of the Earth's atmosphere, compared with the size of the Earth, is in about the same ratio as the thickness of a coat of shellac on a schoolroom globe is to the diameter of the globe. That's the air that nurtures us and almost all other life on Earth, that protects us from deadly ultraviolet light from the sun, that through the greenhouse effect brings the surface temperature above the freezing point. (Without the greenhouse effect, the entire Earth would plunge below the freezing point of water and we'd all be dead.) Now that atmosphere, so thin and fragile, is under assault by our technology. We are pumping all kinds of stuff into it. You know about the concern that chlorofluorocarbons are depleting the ozone layer; and that carbon dioxide and methane and other greenhouse gases are producing global warming, a steady trend amidst fluctuations produced by volcanic eruptions and other sources. Who knows what other challenges we are posing to this vulnerable layer of air that we haven't been wise enough to foresee?

In our daily lives, we enjoy the pervasive benefits of long-lived robotic spacecraft that provide high-capacity worldwide telecommunications; reconnaissance of Earth’s solid surface and oceans, with far-reaching cultural and environmental implications; much-improved weather and climatic forecasts; improved knowledge about the terrestrial effects of the Sun’s radiations; a revolutionary new global navigational system for all manner of aircraft and many other uses both civil and military; and the science of Earth itself as a sustainable abode of life.

In outer space you develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, “Look at that, you son of a bitch.”

Krill, a vital food sources for sea life, is being snatched in vast quantities, with trawlers traveling halfway around the globe, generating ruinous carbon emissions in the form of global supply chains.

Metaphor is important because to deal with, understand, and even ameliorate the fix we are now in over global change requires us to know the true nature of the Earth and imagine it as the largest living thing in the solar system, not something inanimate like that disreputable contraption ‘spaceship Earth’.

No one’s going to be able to operate without a grounding in the basic sciences. Language would be helpful, although English is becoming increasingly international. And travel. You have to have a global attitude.

Nuclear energy and foreign policy cannot coexist on the planet. The more deep the secret, the greater the determination of every nation to discover and exploit it. Nuclear energy insists on global government, on law, on order, and on the willingness of the community to take the responsibility for the acts of the individual. And to what end? Why, for liberty, first of blessings. Soldier, we await you, and if the

Ours is a brand-new world of allatonceness [all-at-once-ness]. “Time” has ceased, “space” has vanished. We now live in a global village … a simultaneous happening. … The new electronic interdependence recreates the world in the image of a global village.

Some of the scientists, I believe, haven’t they been changing their opinion a little bit on global warming? There’s a lot of differing opinions and before we react I think it’s best to have the full accounting, full understanding of what’s taking place.

The big damages come if the climate sensitivity to greenhouse gases turns out to be high [causing greater global warming than current projections.] Then it’s not a bullet headed at us, but a thermonuclear warhead.

The carbon output that melts the ice in the Arctic also causes ocean acidification, which results from the ocean absorbing excess carbon dioxide from the atmosphere (the same carbon dioxide that is the primary cause of global warming, hence the nickname “the other carbon problem”).

The electric age ... established a global network that has much the character of our central nervous system.

The famous set of pictures taken from the moon, [celebrate] the birth of a global consciousness that will help build a peaceful future for humankind. That future is in the hands of those who dedicate their lives to explore Teilhard de Chardin’s three infinities: the infinitely big, the infinitely small, and the infinitely complex. And from all the beauty they discover while crossing perpetually receding frontiers, they develop for nature and for humankind an infinite love.

The gold rush in Madre de Dios, Peru, exceeds the combined effects of all other causes of forest loss in the region, including from logging, ranching and agriculture. This is really important because we’re talking about a global biodiversity hotspot. The region’s incredible flora and fauna is being lost to gold fever.

The importance of rice will grow in the coming decades because of potential changes in temperature, precipitation, and sea-level rise, as a result of global warming. Rice grows under a wide range of latitudes and altitudes and can become the anchor of food security in a world confronted with the challenge of climate change.

The Industrial Revolution as a whole was not designed. It took shape gradually as industrialists and engineers figured out how to make things. The result is that we put billions of pounds of toxic materials in the air, water and soil every year and generate gigantic amounts of waste. If our goal is to destroy the world—to produce global warming and toxicity and endocrine disruption—we're doing great.

The microbial global brain—gifted with long-range transport, data trading, genetic variants … and the ability to reinvent genomes—began its operations some 91 trillion bacterial generations before the birth of the Internet. Ancient bacteria, if they functioned like those today, had mastered the art of worldwide information exchange. … The earliest microorganisms would have used planet-sweeping currents of wind and water to carry the scraps of genetic code…

The number of hypotheses and theories about climate change are numerous. Quite naturally they have caught the public attention, as any proof of past climactic change points to the possibility of future climate change, which inevitably will have significant implications for global economics.

The prediction of nuclear winter is drawn not, of course, from any direct experience with the consequences of global nuclear war, but rather from an investigation of the governing physics. (The problem does not lend itself to full experimental verification—at least not more than once.)[co-author with American atmospheric chemist Richard P. Turco (1943- )]

The weight of our civilization has become so great, it now ranks as a global force and a significant wild card in the human future along with the Ice Ages and other vicissitudes of a volatile and changeable planetary system

The world won’t come to an end, but the incidence of disasters will have a very big impact, and in ways we can't predict. … Rises in seas levels will displace millions of people. It’s estimated there will be 150 million refugees by 2050, homeless as a result of global warming. It’s how we deal with these problems that is as much the challenge as tackling the causes of global warming.

The world's forests need to be seen for what they are—giant global utilities, providing essential public services to humanity on a vast scale. They store carbon, which is lost to the atmosphere when they burn, increasing global warming. The life they support cleans the atmosphere of pollutants and feeds it with moisture. They act as a natural thermostat, helping to regulate our climate and sustain the lives of 1.4 billion of the poorest people on this Earth. And they do these things to a degree that is all but impossible to imagine.

These days, engineering is seldom a solo effort and is increasingly a global endeavour.

Think of a single problem confronting the world today. Disease, poverty, global warming… If the problem is going to be solved, it is science that is going to solve it. Scientists tend to be unappreciated in the world at large, but you can hardly overstate the importance of the work they do. If anyone ever cures cancer, it will be a guy with a science degree. Or a woman with a science degree.

Today when the public thinks of the products of science it is likely to think about environmental problems, an unproductive armament industry, careless or dishonest 'scientific' reports, Livermore cheers for 'nukes forever' and a huge amount of self-serving noise on every subject from global warming to 'the face of God'.

We should look upon agriculture not just as a food-producing machine for the urban population, but as the major source of skilled and remunerative employment and a hub for global outsourcing.

We should stop the non-scientific, pseudo-scientific, and anti-scientific nonsense emanating from the right wing, and start demanding immediate action to reduce global warming and prevent catastrophic climate change that may be on our horizon now. We must not let the [Bush] Administration distort science and rewrite and manipulate scientific reports in other areas. We must not let it turn the Environmental Protection Agency into the Environmental Pollution Agency.

We’ve arranged a global civilization in which most critical elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.

What we’re dealing with is so vast and so global that it really does need to be energized and kicked into high gear. Basically what’s going on is we are overfishing–the biggest danger–there are lots of things going on with the oceans that are threatening them.

While no one can ascribe a single weather event to climate change with any degree of scientific certainty, higher maximum temperatures are one of the most predictable impacts of accelerated global warming, and the parallels—between global climate change and global terrorism—are becoming increasingly obvious.