HISTORY OF CHEMISTRY

By 1000 BC, the ancient civilizations were using technologies that would form the basis of the various branches of chemistry. Extracting metal from their ores, making pottery and glazes, fermenting beer and wine, making pigments for cosmetics and painting, extracting chemicals from plants for medicine and perfume, making cheese, dying cloth, tanning leather, rendering fat into soap, making glass, and making alloys like bronze.
Philosophical attempts to explain the nature of matter and its transformations failed. The protoscience of alchemy also failed, but by experimentation and recording the results set the stage for science. Modern chemistry begins to emerge when a clear distinction is made between chemistry and alchemy by Robert Boyle in his work The Sceptical Chymist (1661). Chemistry then becomes a full-fledged science when Antoine Lavoisier develops his law of conservation of mass, which demands careful measurements and quantitative observations of chemical phenomena. So, while both alchemy and chemistry are concerned with the nature of matter and its transformations, it is only the chemists who apply the scientific method. The history of chemistry is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs.[1]
From fire to atomism
Arguably the first chemical reaction that was used in a controlled manner by mankind was fire. However, for millennia, in absence of a scientific understanding, fire was simply a mystical force that could transform one substance into another (burn the wood, or boil the water) while producing heat and light. Fire affected many aspects of early societies, ranging from the most simple facets of everyday life, such as cooking and habitat lighting, to more advanced technologies, such as pottery, bricks, and smelting of metals to make tools.
Philosophical attempts to rationalize why different substances have different properties (color, density, smell), exist in different states (gaseous, liquid, and solid), and react in a different manner when exposed to environments, for example to water or fire or temperature changes, led ancient philosophers to postulate the first theories on nature and chemistry. The history of such philosophical theories that relate to chemistry, can probably be traced back to every single ancient civilization. The common aspect in all these theories was the attempt to identify a small number of primary elements that make up all the various substances in nature. Substances like air, water, and soil/earth, energy forms, such as fire and light, and more abstract concepts such as ideas, aether, and heaven, were common in ancient civilizations even in absence of any cross-fertilization; for example in Greek, Indian, Mayan, and ancient Chinese philosophies all considered air, water, earth and fire as primary elements.[citation needed]
Atomism can be traced back to ancient Greece and ancient India.[2] Greek atomism dates back to 440 BC, as what might be indicated by the book De Rerum Natura (The Nature of Things)[3] written by the Roman Lucretius[4] in 50 BC. In the book was found ideas traced back to Democritus and Leucippus, who declared that atoms were the most indivisible part of matter. This coincided with a similar declaration by Indian philosopher Kanada in his Vaisheshika sutras around the same time period.[2] By similar means discussed the existence of gases. What Kanada declared by sutra, Democritus declared by philosophical musing. Both suffered from a lack of empirical data. Without scientific proof, the existence of atoms was easy to deny. Aristotle opposed the existence of atoms in 330 BC; and the atomism of the Vaisheshika school was also opposed for a long time.[citation needed]
Much of the early development of purification methods is described by Pliny the Elder in his Naturalis Historia. He made attempts to explain those methods, as well as making acute observations of the state of many minerals.
[edit] The rise of metallurgy
Main articles: History of ferrous metallurgy and History of metallurgy in the Indian subcontinent
It was fire that led to the discovery of glass and the purification of metals which in turn gave way to the rise of metallurgy.[citation needed] During the early stages of metallurgy, methods of purification of metals were sought, and gold, known in ancient Egypt as early as 2600 BC, became a precious metal. The discovery of alloys heralded the Bronze Age. After the Bronze Age, the history of metallurgy was marked by which army had better weaponry. Countries in Eurasia had their heyday when they made the superior alloys, which, in turn, made better armour and better weapons. This often determined the outcomes of battles.[citation needed] Significant progress in metallurgy and alchemy was made in ancient India.[5]
[edit] The philosopher's stone and the rise of alchemy
Main article: Alchemy

"Renel the Alchemist", by Sir William Douglas, 1853
Many people were interested in finding a method that could convert cheaper metals into gold. The material that would help them do this was rumored to exist in what was called the philosopher's stone. This led to the protoscience called alchemy. Alchemy was practiced by many cultures throughout history and often contained a mixture of philosophy, mysticism, and protoscience.[citation needed]
Alchemy not only sought to turn base metals into gold, but especially in a Europe rocked by bubonic plague, there was hope that alchemy would lead to the development of medicines to improve people's health. The holy grail of this strain of alchemy was in the attempts made at finding the elixir of life, which promised eternal youth. Neither the elixir nor the philosopher's stone were ever found. Also, characteristic of alchemists was the belief that there was in the air an "ether" which breathed life into living things.[citation needed] Practitioners of alchemy included Isaac Newton, who remained one throughout his life.
[edit] Problems encountered with alchemy
There were several problems with alchemy, as seen from today's standpoint. There was no systematic naming system for new compounds, and the language was esoteric and vague to the point that the terminologies meant different things to different people. In fact, according to The Fontana History of Chemistry (Brock, 1992):
The language of alchemy soon developed an arcane and secretive technical vocabulary designed to conceal information from the uninitiated. To a large degree, this language is incomprehensible to us today, though it is apparent that readers of Geoffery Chaucer's Canon's Yeoman's Tale or audiences of Ben Jonson's The Alchemist were able to construe it sufficiently to laugh at it.[6]
Chaucer's tale exposed the more fraudulent side of alchemy, especially the manufacture of counterfeit gold from cheap substances. Soon after Chaucer, Dante Alighieri also demonstrated an awareness of this fraudulence, causing him to consign all alchemists to the Inferno in his writings. Soon after, in 1317, the Avignon Pope John XXII ordered all alchemists to leave France for making counterfeit money. A law was passed in England in 1403 which made the "multiplication of metals" punishable by death. Despite these and other apparently extreme measures, alchemy did not die. Royalty and privileged classes still sought to discover the philosopher's stone and the elixir of life for themselves.[7]
There was also no agreed-upon scientific method for making experiments reproducible. Indeed many alchemists included in their methods irrelevant information such as the timing of the tides or the phases of the moon. The esoteric nature and codified vocabulary of alchemy appeared to be more useful in concealing the fact that they could not be sure of very much at all. As early as the 14th century, cracks seemed to grow in the facade of alchemy; and people became sceptical.[citation needed] Clearly, there needed to be a scientific method where experiments can be repeated by other people, and results needed to be reported in a clear language that laid out both what is known and unknown.
[edit] From alchemy to chemistry
[edit] Early chemists
See also: Timeline of chemistry and Alchemy and chemistry in Islam

Jabir ibn Hayyan (Geber), an Arabic alchemist whose experimental research laid the foundations for chemistry.
In the Arab world, the Muslims were translating the works of the ancient Greeks into Arabic and were experimenting with scientific ideas.[8] The development of the modern scientific method was slow and arduous, but an early scientific method for chemistry began emerging among early Muslim chemists, beginning with the 9th century chemist Jabir ibn Hayyan (known as "Geber" in Europe), who is "considered by many to be the father of chemistry".[9][10][11][12] He introduced a systematic and experimental approach to scientific research based in the laboratory, in contrast to the ancient Greek and Egyptian alchemists whose works were often allegorical and unintelligble.[13] He also invented and named the alembic (al-anbiq), chemically analyzed many chemical substances, composed lapidaries, distinguished between alkalis and acids, and manufactured hundreds of drugs.[14]
Among other influential Muslim chemists, Ja'far al-Sadiq,[15] Alkindus,[16] Abū al-Rayhān al-Bīrūnī,[17] Avicenna[18] and Ibn Khaldun refuted the practice of alchemy and the theory of the transmutation of metals; and Tusi described an early version of the conservation of mass, noting that a body of matter is able to change but is not able to disappear.[19] Rhazes refuted Aristotle's theory of four classical elements for the first time and set up the firm foundations of modern chemistry, using the laboratory in the modern sense, designing and describing more than twenty instruments, many parts of which are still in use today, such as a crucible, decensory, cucurbit or retort for distillation, and the head of a still with a delivery tube (ambiq, Latin alembic), and various types of furnace or stove.[20]

Agricola, author of De re metallica
For the more honest practitioners in Europe, alchemy became an intellectual pursuit after early Arabic alchemy became available through Latin translation, and over time, they got better at it. Paracelsus (1493-1541), for example, rejected the 4-elemental theory and with only a vague understanding of his chemicals and medicines, formed a hybrid of alchemy and science in what was to be called iatrochemistry. Paracelsus was not perfect in making his experiments truly scientific. For example, as an extension of his theory that new compounds could be made by combining mercury with sulfur, he once made what he thought was "oil of sulfur". This was actually dimethyl ether, which had neither mercury nor sulfur.[citation needed]
Practical attempts to improve the refining of ores and their extraction to smelt metals was an important source of information for early chemists, among them Georg Agricola (1494–1555), who published his great work De re metallica in 1556. His approach removed the mysticism associated with the subject, creating the practical base upon which others could build. The work describes the many kinds of furnace used to smelt ore, and stimulated interest in minerals and their composition. It is no coincidence that he gives numerous references to the earlier author, Pliny the Elder and his Naturalis Historia.
In 1605, Sir Francis Bacon published The Proficience and Advancement of Learning, which contains a description of what would later be known as the scientific method.[21] In 1615 Jean Beguin publishes the Tyrocinium Chymicum, an early chemistry textbook, and in it draws the first-ever chemical equation.[22]

Robert Boyle, one of the co-founders of modern chemistry through his use of proper experimentation, which further separated chemistry from alchemy
Robert Boyle (1627–1691) is considered to have refined the modern scientific method for alchemy and to have separated chemistry further from alchemy.[23] Robert Boyle was an atomist, but favoured the word corpuscle over atoms. He comments that the finest division of matter where the properties are retained is at the level of corpuscles.
Boyle was credited with the discovery of Boyle's Law. He is also credited for his landmark publication The Sceptical Chymist, where he attempts to develop an atomic theory of matter, with no small degree of success. Despite all these advances, the person celebrated as the "father of modern chemistry" is Antoine Lavoisier who developed his law of conservation of mass in 1789, also called Lavoisier's Law.[24] With this, chemistry acquired a strict quantitative nature, allowing reliable predictions to be made.
In 1754, Joseph Black isolated carbon dioxide, which he called "fixed air".[25] Carl Wilhelm Scheele and Joseph Priestly independently isolated oxygen, called by Priestly "dephlogisticated air" and Scheele "fire air".[26][27]
Joseph Proust proposed the law of definite proportions, which states that elements always combine in small, whole number ratios to form compounds.[28] In 1800, Alessandro Volta devised the first chemical battery, thereby founding the discipline of electrochemistry.[29] In 1803, John Dalton proposed Dalton's Law, which describes relationship between the components in a mixture of gases and the relative pressure each contributes to that of the overall mixture.[30]
[edit] Antoine Lavoisier

Portrait of Monsieur Lavoisier and his wife, by Jacques-Louis David
Although the archives of chemical research draw upon work from ancient Babylonia, Egypt, and especially the Arabs and Persians after Islam, modern chemistry flourished from the time of Antoine Lavoisier, who is regarded as the "father of modern chemistry", particularly for his discovery of the law of conservation of mass, and his refutation of the phlogiston theory of combustion in 1783. (Phlogiston was supposed to be an imponderable substance liberated by flammable materials in burning.) Mikhail Lomonosov independently established a tradition of chemistry in Russia in the 18th century.[citation needed] Lomonosov also rejected the phlogiston theory, and anticipated the kinetic theory of gases.[citation needed] He regarded heat as a form of motion, and stated the idea of conservation of matter.
[edit] The vitalism debate and organic chemistry
After the nature of combustion (see oxygen) was settled, another dispute, about vitalism and the essential distinction between organic and inorganic substances, was revolutionized by Friedrich Wöhler's accidental synthesis of urea from inorganic substances in 1828. Never before had an organic compound been synthesized from inorganic material.[citation needed] This opened a new research field in chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The most important among them are mauve, magenta, and other synthetic dyes, as well as the widely used drug aspirin. The discovery of the artificial synthesis of urea contributed greatly to the theory of isomerism, as the empirical chemical formulas for urea and ammonium cyanate can be expressed similarly.
[edit] Disputes about atomism after Lavoisier

Bust of John Dalton by Chantrey
Throughout the 19th century, chemistry was divided between those who followed the atomic theory of John Dalton and those who did not, such as Wilhelm Ostwald and Ernst Mach.[31] Although such proponents of the atomic theory as Amedeo Avogadro and Ludwig Boltzmann made great advances in explaining the behavior of gases, this dispute was not finally settled until Jean Perrin's experimental investigation of Einstein's atomic explanation of Brownian motion in the first decade of the 20th century.[31]
Well before the dispute had been settled, many had already applied the concept of atomism to chemistry. A major example was the ion theory of Svante Arrhenius which anticipated ideas about atomic substructure that did not fully develop until the 20th century. Michael Faraday was another early worker, whose major contribution to chemistry was electrochemistry, in which (among other things) a certain quantity of electricity during electrolysis or electrodeposition of metals was shown to be associated with certain quantities of chemical elements, and fixed quantities of the elements therefore with each other, in specific ratios.[citation needed] These findings, like those of Dalton's combining ratios, were early clues to the atomic nature of matter.
[edit] The periodic table
Main article: History of the periodic table

Dmitri Mendeleev, responsible for the periodic table.
For many decades, the list of known chemical elements had been steadily increasing. A great breakthrough in making sense of this long list (as well as in understanding the internal structure of atoms as discussed below) was Dmitri Mendeleev and Lothar Meyer's development of the periodic table, and particularly Mendeleev's use of it to predict the existence and the properties of germanium, gallium, and scandium, which Mendeleev called ekasilicon, ekaaluminium, and ekaboron respectively. Mendeleev made his prediction in 1870; gallium was discovered in 1875, and was found to have roughly the same properties that Mendeleev predicted for it.[citation needed]
[edit] The modern definition of chemistry
Classically, before the 20th century, chemistry was defined as the science of the nature of matter and its transformations. It was therefore clearly distinct from physics which was not concerned with such dramatic transformation of matter. Moreover, in contrast to physics, chemistry was not using much of mathematics. Even some were particularly reluctant to using mathematics within chemistry. For example, Auguste Comte wrote in 1830:
Every attempt to employ mathematical methods in the study of chemical questions must be considered profoundly irrational and contrary to the spirit of chemistry.... if mathematical analysis should ever hold a prominent place in chemistry -- an aberration which is happily almost impossible -- it would occasion a rapid and widespread degeneration of that science.
However, in the second part of the 19th century, the situation changed and August Kekule wrote in 1867:
I rather expect that we shall someday find a mathematico-mechanical explanation for what we now call atoms which will render an account of their properties.
After the discovery by Ernest Rutherford and Niels Bohr of the atomic structure in 1912, and by Marie and Pierre Curie of radioactivity, scientists had to change their viewpoint on the nature of matter. The experience acquired by chemists was no longer pertinent to the study of the whole nature of matter but only to aspects related to the electron cloud surrounding the atomic nuclei and the movement of the latter in the electric field induced by the former (see Born-Oppenheimer approximation). The range of chemistry was thus restricted to the nature of matter around us in conditions which are not too far from standard conditions for temperature and pressure and in cases where the exposure to radiation is not too different from the natural microwave, visible or UV radiations on Earth. Chemistry was therefore re-defined as the science of matter that deals with the composition, structure, and properties of substances and with the transformations that they undergo.[citation needed] However the meaning of matter used here relates explicitly to substances made of atoms and molecules, disregarding the matter within the atomic nuclei and its nuclear reaction or matter within highly ionized plasmas. Nevertheless the field of chemistry is still, on our human scale, very broad and the claim that chemistry is everywhere is accurate.
[edit] Quantum chemistry
Main article: Quantum chemistry
Some view the birth of quantum chemistry in the discovery of the Schrödinger equation and its application to the hydrogen atom in 1926.[citation needed] However, the 1927 article of Walter Heitler and Fritz London[32] is often recognised as the first milestone in the history of quantum chemistry.[33] This is the first application of quantum mechanics to the diatomic hydrogen molecule, and thus to the phenomenon of the chemical bond. In the following years much progress was accomplished by Edward Teller, Robert S. Mulliken, Max Born, J. Robert Oppenheimer, Linus Pauling, Erich Hückel, Douglas Hartree, Vladimir Aleksandrovich Fock, to cite a few.[citation needed]
Still, skepticism remained as to the general power of quantum mechanics applied to complex chemical systems.[citation needed] The situation around 1930 is described by Paul Dirac:[34]
The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. It therefore becomes desirable that approximate practical methods of applying quantum mechanics should be developed, which can lead to an explanation of the main features of complex atomic systems without too much computation.
Hence the quantum mechanical methods developed in the 1930s and 1940s are often referred to as theoretical molecular or atomic physics to underline the fact that they were more the application of quantum mechanics to chemistry and spectroscopy than answers to chemically relevant questions.
In the 1940s many physicists turned from molecular or atomic physics to nuclear physics (like J. Robert Oppenheimer or Edward Teller). In 1951, a milestone article in quantum chemistry is the seminal paper of Clemens C. J. Roothaan on Roothaan equations.[35] It opened the avenue to the solution of the self-consistent field equations for small molecules like hydrogen or nitrogen. Those computations were performed with the help of tables of integrals which were computed on the most advanced computers of the time.[citation needed]
[edit] Molecular biology and biochemistry
Main articles: History of molecular biology and History of biochemistry
By the mid 20th century, in principle, the integration of physics and chemistry was extensive, with chemical properties explained as the result of the electronic structure of the atom; Linus Pauling's book on The Nature of the Chemical Bond used the principles of quantum mechanics to deduce bond angles in ever-more complicated molecules. However, though some principles deduced from quantum mechanics were able to predict qualitatively some chemical features for biologically relevant molecules, they were, till the end of the 20th century, more a collection of rules, observations, and recipes than rigorous ab initio quantitative methods.[citation needed]

Diagrammatic representation of some key structural features of DNA
This heuristic approach triumphed in 1953 when James Watson and Francis Crick deduced the double helical structure of DNA by constructing models constrained by and informed by the knowledge of the chemistry of the constituent parts and the X-ray diffraction patterns obtained by Rosalind Franklin.[36] This discovery lead to an explosion of research into the biochemistry of life.
In the same year, the Miller-Urey experiment demonstrated that basic constituents of protein, simple amino acids, could themselves be built up from simpler molecules in a simulation of primordial processes on Earth. Though many questions remain about the true nature of the origin of life, this was the first attempt by chemists to study hypothetical processes in the laboratory under controlled conditions.[citation needed]
In 1983 Kary Mullis devised a method for the in-vitro amplification of DNA, known as the polymerase chain reaction (PCR), which revolutionized the chemical processes used in the laboratory to manipulate it. PCR could be used to synthesize specific pieces of DNA and made possible the sequencing of DNA of organisms, which culminated in the huge human genome project.
An important piece in the double helix puzzle was solved by one of Pauling's student Matthew Meselson and Frank Stahl, the result of their collaboration (Meselson-Stahl experiment) has been called as "the most beatiful experiment in biology".
They used a centrifugation technique that sorted molecules according to differences in weight. Because nitrogen atoms are a component of DNA, they were labelled and therefore tracked in replication in bacteria.
[edit] Chemical industry
Main article: Chemical industry
The later part of the nineteenth century saw a huge increase in the exploitation of petroleum extracted from the earth for the production of a host of chemicals and largely replaced the use of whale oil, coal tar and naval stores used previously. Large scale production and refinement of petroleum provided feedstocks for liquid fuels such as gasoline and diesel, solvents, lubricants, asphalt, waxes, and for the production of many of the common materials of the modern world, such as synthetic fibers, plastics, paints, detergents, pharmaceuticals, adhesives and ammonia as fertilizer and for other uses. Many of these required new catalysts and the utilization of chemical engineering for their cost-effective production.
In the mid-twentieth century, control of the electronic structure of semiconductor materials was made precise by the creation of large ingots of extremely pure single crystals of silicon and germanium. Accurate control of their chemical composition by doping with other elements made the production of the solid state transistor in 1951 and made possible the production of tiny integrated circuits for use in electronic devices, especially computers.

GLOBAL WARMING

Global climate change impacts in the United States are spelled out with renewed authority in a report released June 16 by the federal government.
The report's key information has been well reported here and in Earth Under Fire and other books, but bears repeating in its straightforward language and up-to-date numbers.
Human activities have led to large increases in heat-trapping gases over the past century. The global warming of the past 50 years is due primarily to this human-induced increase. Global average temperature and sea level have increased, and precipitation patterns have changed.
Human “fingerprints” also have been identified in many other aspects of the climate system, including changes in ocean heat content, precipitation, atmospheric moisture, plant and animal health and location, and Arctic sea ice.
In the U.S., the amount of rain falling in the heaviest downpours has increased approximately 20 percent on average in the past century.
Many types of extreme weather events, such as heat waves and regional droughts, have become more frequent and intense during the past 40 to 50 years. The destructive energy of Atlantic hurricanes has increased... In the eastern Pacific, the strongest hurricanes have become stronger since the 1980s, even while the total number of storms has decreased.
Sea level has risen along most of the U.S. coast over the last 50 years, and will rise more in the future. Arctic sea ice is declining rapidly and this is very likely to continue. Global temperatures are projected to continue to rise over this century.
Whether by 2-3 degrees F or more than 11 degrees depends on a number of factors, including the amount of heat-trapping gas emissions humans continue to allow and how sensitive the climate is to those emissions. Lower emissions of heat-trapping gases will delay the appearance of climate change impacts andlessen their magnitude.
Unless the rate of emissions is substantially reduced, impacts are expected to become increasingly severe for more people and places.
For more from this report, please go to the Temperate Zone page.
Obama's Climate Team Moves to Regulate Greenhouse Gases as Research Shows Global Warming Continues at High Rates
President Barack Obama's new Environmental Protection Agency chief Lisa Jackson has moved to put CO2 and other greenhouse gases under regulation by the Clean Air Act. In one of the most anticipated early actions by the new Administration, the EPA issued a proposed finding on April 17 that these gases endanger human health and well-being. When made final, this will clear the way for regulation of vehicle exhaust, which is the source of about 30 percent of US carbon dioxide emissions.
This is one of the most visible of the climate actions springing from members of the President's new Cabinet, which includes leading scientists and informed diplomats. As they took their posts, working scientists announced in two international meetings that many factors in rapid global warming were getting worse or running at rates which only a few years ago were thought to be extreme.
Besides Jackson, who an was an experienced state environment leader before taking over at EPA, Obama appointed former EPA head Carol Browner to a new post of White House climate and energy chief; Nobel Prize winner Stephen Chu as Secretary of Energy; Harvard professor John Holdren, who has been outspoken on the dangers of climate disruption, as Presidential science advisor; and acclaimed ocean scientist Jane Lubchenco as head of NOAA.
Secretary of State Hillary Clinton replaced George Bush's footdragging international climate negotiators with a team lead by Todd Stern. One of his first actions was to announce to international climate talks in Bonn that "the science is clear, and the threat is real. The facts on the ground are outstripping the worst case scenarios. The costs of inaction-or inadequate actions-are unacceptable." The Bonn talks are preliminary to crucial UN Climate Convention meetings in Copenhagen in December [[link: http://unfccc.int/2860.php]], at which nations have promised to agree to sharp limits on greenhouse gases, replacing the Kyoto Protocol. Many national issues and roadblocks remain, however, prime of which is the world recession which dominates other international meetings.
The EPA finding, although initially focused directly on vehicle emissions, will lead under the Clean Air Act to regulation of greenhouse gas emissions from power plants, source of nearly half of American CO2. Congress is also proposing control of emissions using a cap and trade process familiar to many from previous Clean Air Act procedures to limit sulphur pollution from coal burning plants. A comprehensive climate and energy bill, drafted by Rep. Henry Waxman of California and Rep. Edward Markey of Massachusetts, will be debated in the House this spring. Reactions to the proposed legislation are being posted by many business and environmental groups and will surely intensify as the bill is amended and moves toward a vote later this year.
The urgency of climate action is even greater now because some recent observations are at or beyond the highest projections of previous reports. Scientific studies updating the IPCC assessment of 2007 show that more CO2 is being put into the air than ever before. Rates of change of global mean temperature, sea level rise, ice sheet changes in Greenland and the edges of Antarctica, and ocean chemical changes are running at the highest projections of the 2007 IPCC. In February 2009 at the annual meeting of the American Association for the Advancement of Science, Dr. Chris Field of the Carnegie Institute also reported that some major ways that the earth naturally absorbs CO2 were less efficient now, leaving more of the gas in the air. I heard him say that because of all this, we are "on a trajectory of climate... that has not been explored."
Not every indication of climate is changing this rapidly, but most scientists now predict a 5 degree F or more temperature increase and at least three feet of sea level rise before 2100 if things continue in this way. The changes documented in these website pages and my book occurred during a time of just over one degree of warming.
Every citizen of the world needs to be aware of rapid climate change:
1. Understand the problem, its causes and threats.2. Let your leaders know the facts and that you expect them to act.3. Do something today to reduce greenhouse gas output - please Take action.

NATURAL PRODUCTS CHEMISTRY

A natural product is a chemical compound or substance produced by a living organism - found in nature that usually has a pharmacological or biological activity for use in pharmaceutical drug discovery and drug design. A natural product can be considered as such even if it can be prepared by total synthesis.
Not all natural products can be fully synthesized and many natural products have very complex structures that are too difficult and expensive to synthesize on an industrial scale. These include drugs such as penicillin, morphine, and paclitaxel (Taxol). Such compounds can only be harvested from their natural source - a process which can be tedious, time consuming, and expensive, as well as being wasteful on the natural resource. For example, one yew tree would have to be cut down to extract enough paclitaxel from its bark for a single dose.[1] Furthermore, the number of structural analogues that can be obtained from harvesting is severely limited.
A further problem is that isolates often work differently than the original natural products which have synergies and may combine, say, antimicrobial compounds with compounds that stimulate various pathways of the immune system:
Many higher plants contain novel metabolites with antimicrobial and antiviral properties. However, in the developed world almost all clinically used chemotherapeutics have been produced by in vitro chemical synthesis. Exceptions, like taxol and vincristine, were structurally complex metabolites that were difficult to synthesize in vitro. Many non-natural, synthetic drugs cause severe side effects that were not acceptable except as treatments of last resort for terminal diseases such as cancer. The metabolites discovered in medicinal plants may avoid the side effect of synthetic drugs, because they must accumulate within living cells.[2]
Semisynthetic procedures can sometimes get around these problems. This often involves harvesting a biosynthetic intermediate from the natural source, rather than the final (lead) compound itself. The intermediate could then be converted to the final product by conventional synthesis. This approach can have two advantages. First, the intermediate may be more easily extracted in higher yield than the final product itself. Second, it may allow the possibility of synthesizing analogues of the final product. The semisynthetic penicillins are an illustration of this approach. Another recent example is that of paclitaxel. It is manufactured by extracting 10-deacetylbaccatin III from the needles of the yew tree, then carrying out a four-stage synthesis.
Despite the potential limitations of natural products detailed above, these small molecules provide the source or inspiration for the majority of FDA-approved agents and continue to be one of the major sources of inspiration for drug discovery. In particular, these compounds are important in the treatment of life-threatening conditions.[3]

Natural sources
Natural products may be extracted from tissues of terrestrial plants, marine organisms or microorganism fermentation broths. A crude (untreated) extract from any one of these sources typically contains novel, structurally diverse chemical compounds, which the natural environment is a rich source of.
Chemical diversity in nature is based on biological and geographical diversity, so researchers travel around the world obtaining samples to analyze and evaluate in drug discovery screens or bioassays. This effort to search for natural products is known as bioprospecting.
[edit] Screening of natural products
Pharmacognosy provides the tools to identify, select and process natural products destined for medicinal use. Usually, the natural product compound has some form of biological activity and that compound is known as the active principle - such a structure can act as a lead compound (not to be confused with compounds containing the element lead). Many of today's medicines are obtained directly from a natural source.
On the other hand, some medicines are developed from a lead compound originally obtained from a natural source. This means the lead compound:
can be produced by total synthesis, or
can be a starting point (precursor) for a semisynthetic compound, or
can act as a template for a structurally different total synthetic compound.
This is because most biologically active natural product compounds are secondary metabolites with very complex structures. This has an advantage in that they are extremely novel compounds but this complexity also makes many lead compounds' synthesis difficult and the compound usually has to be extracted from its natural source - a slow, expensive and inefficient process. As a result, there is usually an advantage in designing simpler analogues.
[edit] The plant kingdom
Plants have always been a rich source of lead compounds (e.g. morphine, cocaine, digitalis, quinine, tubocurarine, nicotine, and muscarine). Many of these lead compounds are useful drugs in themselves (e.g. morphine and quinine), and others have been the basis for synthetic drugs (e.g. local anaesthetics developed from cocaine). Clinically useful drugs which have been recently isolated from plants include the anticancer agent paclitaxel (Taxol) from the yew tree, and the antimalarial agent artemisinin from Artemisia annua.
Plants provide a large bank of rich, complex and highly varied structures which are unlikely to be synthesized in laboratories. Furthermore, evolution has already carried out a screening process itself whereby plants are more likely to survive if they contain potent compounds which deter animals or insects from eating them. Even today, the number of plants that have been extensively studied is relatively very few and the vast majority have not been studied at all.
[edit] The microbial world
Microorganisms such as bacteria and fungi have been invaluable for discovering drugs and lead compounds. These microorganisms produce a large variety of antimicrobial agents which have evolved to give their hosts an advantage over their competitors in the microbiological world.
The screening of microorganisms became highly popular after the discovery of penicillin. Soil and water samples were collected from all over the world in order to study new bacterial or fungal strains, leading to an impressive arsenal of antibacterial agents such as the cephalosporins, tetracyclines, aminoglycosides, rifamycins, and chloramphenicol.
Although most of the drugs derived from microorganisms are used in antibacterial therapy, some microbial metabolites have provided lead compounds in other fields of medicine. For example, asperlicin - isolated from Aspergillus alliaceus - is a novel antagonist of a peptide hormone called cholecystokinin (CCK) which is involved in the control of appetite. CCK also acts as a neurotransmitter in the brain and is thought to be involved in panic attacks. Analogues of asperlicin may therefore have potential in treating anxiety. Other examples include the fungal metabolite lovastatin, which was the lead compound for a series of drugs that lower cholesterol levels, and another fungal metabolite called ciclosporin which is used to suppress the immune response after transplantation operations.
[edit] The marine world
In recent years, there has been a great interest in finding lead compounds from marine sources. Coral, sponges, fish, and marine microorganisms have a wealth of biologically potent chemicals with interesting inflammatory, antiviral, and anticancer activity. For example, curacin A is obtained from a marine cyanobacterium and shows potent antitumor activity. Other antitumor agents derived from marine sources include eleutherobin, discodermolide, bryostatins, dolostatins, and cephalostatins.
[edit] Animal sources
Animals can sometimes be a source of new lead compounds. For example, a series of antibiotic peptides were extracted from the skin of the African clawed frog and a potent analgesic compound called epibatidine was obtained from the skin extracts of the Ecuadorian poison frog.
[edit] Venoms and toxins
Venoms and toxins from animals, plants, snakes, spiders, scorpions, insects, and microorganisms are extremely potent because they often have very specific interactions with a macromolecular target in the body. As a result, they have proved important tools in studying receptors, ion channels, and enzymes. Many of these toxins are polypeptides (e.g. ɑ-bungarotoxin from cobras). However, non-peptide toxins such as tetrodotoxin from the puffer fish are also extremely potent.
Venoms and toxins have been used as lead compounds in the development of novel drugs. For example, teprotide, a peptide isolated from the venom of the Brazilian viper, was the lead compound for the development of the antihypertensive agents cilazapril and captopril.
The neurotoxins from Clostridium botulinum are responsible for serious food poisoning (botulism), but they have a clinical use as well. They can be injected into specific muscles (such as those controlling the eyelid) to prevent muscle spasm. These toxins prevent cholinergic transmission and could well prove a lead for the development of novel anticholinergic drugs.
[edit] Traditional Medicine
In the past, traditional peoples or ancient civilizations depended greatly on local flora and fauna for their survival. They would experiment with various berries, leaves, roots, animal parts or minerals to find out what effects they had. As a result, many crude drugs were observed by the local healer or shaman to have some medical use. Although some preparations may have been dangerous, or worked by a ceremonial or placebo effect, traditional healing systems usually had a substantial active pharmacopoeia, and in fact most western medicines up until the 1920s were developed this way. Some systems, like traditional Chinese medicine or Ayurveda were fully as sophisticated and as documented systems as western medicine, although they might use different paradigms. Many of these aqueous, ethanolic, distilled, condensed or dried extracts do indeed have a real and beneficial effect, and a study of ethnobotany can give clues as to which plants might be worth studying in more detail. Rhubarb root has been used as a purgative for many centuries. In China, it was called "The General" because of its "galloping charge" and was only used for one or two doses unless processed to reduce its purgative qualities. (Bulk laxatives would follow or be used on weaker patients according to the complex laxative protocols of the medical system.[4]) The most significant chemicals in rhubarb root are anthraquinones, which were used as the lead compounds in the design of the laxative dantron.
The extensive records of Chinese medicine about response to Artemisia preparations for malaria also provided the clue to the novel antimalarial drug artemisinin. The therapeutic properties of the opium poppy (active principle morphine) were known in Ancient Egypt, were those of the Solanaceae plants in ancient Greece (active principles atropine and hyoscine). The snakeroot plant was well regarded in India (active principle reserpine), and herbalists in medieval England used extracts from the willow tree(salicin) and foxglove (active principle digitalis - a mixture of compounds such as digitoxin, digitonin, digitalin). The Aztec and Mayan cultures of Mesoamerica used extracts from a variety of bushes and trees including the ipecacuanha root (active principle emetine), coca bush (active principle cocaine), and cinchona bark (active principle quinine).
It can be challenging to obtain information from practitioners of traditional medicine unless a genuine long term relationship is made. Ethnobotanist Richard Schultes approached the Amazonian shamans with respect, dealing with them on their terms. He became a "depswa" - medicine man - sharing their rituals while gaining knowledge. They responded to his inquiries in kind, leading to new medicines.[5] On the other hand Cherokee herbalist David Winston recounts how his uncle, a medicine priest, would habitually give misinformation to the visiting ethnobotanists. The acupuncturists who investigated Mayan medicine recounted in Wind in the Blood had something to share with the native healers and thus were able to find information not available to anthropologists.[6] The issue of rights to medicine derived from native plants used and frequently cultivated by native healers complicates this issue.
[edit] Isolation and purification
If the lead compound (or active principle) is present in a mixture of other compounds from a natural source, it has to be isolated and purified. The ease with which the active principle can be isolated and purified depends much on the structure, stability, and quantity of the compound. For example, Alexander Fleming recognized the antibiotic qualities of penicillin and its remarkable non-toxic nature to humans, but he disregarded it as a clinically useful drug because he was unable to purify it. He could isolate it in aqueous solution, but whenever he tried to remove the water, the drug was destroyed. It was not until the development of new experimental procedures such as freeze drying and chromatography that the successful isolation and purification of penicillin and other natural products became feasible.