Industrial emissions of greenhouse gases that affect the climate. Green carbon Carbon stored in terrestrial ecosystems e. Black carbon Formed through incomplete combustion of fuels and may be significantly reduced if clean burning technologies are employed. But a mitigation approach needs to consider all these forms of carbon they note, not just one or two:
The History of Climate Science Introduction The fact that carbon dioxide is a 'greenhouse gas' - a gas that prevents a certain amount of heat radiation escaping back to space and thus maintains a generally warm climate on Earth, goes back to an idea that was first conceived, though not specifically with respect to CO2, nearly years ago.
The story of how this important physical property was discovered, how its role in the geological past was evaluated and how we came to understand that its increased concentration, via fossil fuel burning, would adversely affect our future, covers about two centuries of enquiry, discovery, innovation and problem-solving.
Climate Science - the complete timeline, created by jg In the beginning To pick up the scientific trail of what is today known as the Greenhouse Effect, we need to travel back in time to France in the s.
Napoleon, defeated at the Battle of Waterloo just a few years previously, had just died, but somebody who had at one time undertaken significant engineering and academic projects for the late Emperor was now busily engaged on his investigations of the physical world, with a specific interest in the behaviour of heat.
This was Jean Baptiste Joseph Fourier — Fourier had calculated that a planetary object the size of Earth should, quite simply, not be as warm as it is at its distance from the Sun. Therefore, he reasoned, there must be something else apart from incoming solar radiation, some other factor that keeps the planet warmer.
One suggestion he came up with was that the energy coming in from the sun in the form of visible and ultra-violet light known back then as "luminous heat" was easily able to pass through Earth's atmosphere and heat up the planet's surface, but that the "non-luminous heat" now known as infra-red radiation then emitted by the Earth's surface could not make it back in the opposite direction quite so readily.
The warmed air must, he reasoned, act as some kind of insulating blanket. That was about as far as he got with the idea back then, as the detailed measurements required to explore this hypothesis were not available, given the technology of the day.
Climate Science timeline,created by jg s: Tyndall and heat-trapping gases Some 40 years later, the thread was picked up again. To Victorian natural historian and pioneer in Alpine climbing, John Tyndallthe evidence, controversial at the time but now mainstream, clearly indicated that at one time much of northern Europe had been covered by ice-sheets.
However, what was far from clear was how the climate could change in such a drastic manner. Among the possibilities Tyndall considered was variations in the composition of the atmosphere, and via a series of experiments he made the discovery that water-vapour was an important heat-trapping agent.
He also found that carbon dioxide was very good at trapping heat, despite being a trace gas occurring in the hundreds of parts per million ppm range. Hundreds of parts per million may not sound like a lot, but some compounds have important properties at such concentrations: Arrhenius makes a discovery Tyndall's interesting discovery did not completely solve the riddle of the ice ages: But it planted the seed of an idea that was revisited towards the end of the 19th Century by Swedish scientist Svante Arrhenius Reasoning that, because it fluctuated daily, water vapour was continually recycling itself in and out of the atmosphere, he turned his attention to carbon dioxide, a gas resident for a long time in the atmosphere whose concentration was only at that time dramatically changed by major sources such as volcanoes or major drawdowns such as unusual and massive episodes of mineral weathering or the evolution of photosynthetic plants: Arrhenius figured out that an increase in the amount of carbon dioxide in the atmosphere would result in a certain amount of warming.
In addition, it was already known via the Clausius-Clapeyron relation, that warmer air can hold more water vapour: And that additional water vapour would in turn cause further warming - this being a positive feedback, in which carbon dioxide acts as a direct regulator of temperature, and is then joined in that role by more water vapour as temperatures increase.
But could such a change, big enough to cause an ice age, occur? He turned to colleague Arvid Hogbomwho had been investigating natural carbon dioxide cycles, to see if it could. Hogbom had, at the time, started to consider carbon dioxide emissions from factories simple enough if you know, for example, how many tons of coal each factory burns a year.
He had been surprised to find that man-made emission rates were very similar to those occurring in nature. Back in the s, that of course represented a tiny fraction of the fossil fuels that we burn today; but what, they asked themselves, might happen if mankind burnt ever-increasing amounts over many centuries?
Side-tracking from the ice-age research, Arrhenius ran calculations to see what a doubling of carbon dioxide levels might do to temperatures. Back then, at s burning-rates, they didn't see this as a problem: By the time the hypothesis appeared in a popular book that was published inthe burning-rate had already gone up significantly, so in accordance with that change they revised the doubling-time down to a few centuries, but it was still something of a scientific curiosity, the stuff of after-dinner conversations.
The tests began with slightly lower amounts of the gas than would be found in a complete section of the atmosphere from top to bottom - although to truly represent the atmosphere, a cm tube, as opposed to the 30 cm one that was used, would have been closer to the mark.
Then, the amount of carbon dioxide was reduced by a third: Another problem raised at the time was that water vapor also absorbs infra-red radiation, and in the available and by modern standards rather low-resolution spectrographs of the time, the absorption bands of the two gases overlapped one another.
It was thought, therefore, that increasing carbon dioxide would be countered by it being unable to absorb infra-red radiation in bands of the spectrum that the much more abundant water vapor was already blocking.
Not only that, total saturation in the lower atmosphere is not a problem for the Greenhouse Effect: The atmosphere cannot simply be treated as a tube full of gas: This was - and still is - because water vapor in the upper troposphere occurs in concentrations several orders of magnitude less than in the lower troposphere where most of our weather occurs.
As luck would have it, however, nobody took a lot of notice of that and, in effect, the carbon dioxide greenhouse effect hypothesis went to sleep for over two decades. Hulburt and Callendar The trail was picked up again inwhen American physicist E.
The resultant paper appeared in a the journal Physical Review, which tended not to be read by earth and atmospheric scientists and was as a consequence missed by many of them.History of technology - The 20th century: Recent history is notoriously difficult to write, because of the mass of material and the problem of distinguishing the significant from the insignificant among events that have virtually the power of contemporary experience.
In respect to the recent history of technology, however, one fact stands out clearly: . In the midth century, African Americans launched a renewed struggle to claim the civil rights that had long been denied to them.
As they moved to end racial segregation, they called on the nation to live up to its ideals of freedom, equality, and democracy. A Brief Earth History a survey of earth's geology through time and its possible causes both astronomers and geologists have become aware of the important part played by impacting comets and/or asteroids "Introduction to Geology Vol.
2, Earth History," Part I, Early Stages of Earth History, pp. , Wiley, New York, History. CALL dates back to the s, when it was first introduced on university mainframe computers.
The PLATO project, initiated at the University of Illinois in , is an important landmark in the early development of CALL (Marty ). The advent of the microcomputer in the late s brought computing within the range of a wider . Watch video · The s was a decade marked by the Watergate scandal, the growing women's rights, gay rights and environmental movements, and s fashion and music.
Learn more on leslutinsduphoenix.com Back to top. What are the impacts of Global Warming? For decades, greenhouse gases, such as carbon dioxide have been increasing in the atmosphere.