Water, earth, wind and fire. The four elements are making a comeback as scientists warn humans to avoid a collision with the natural world.Forget everything you know about science. Forget – just for a moment – the periodic table with its protons, neutrons and electrons. Forget about gene pools and DNA.
   Now, with modern science out of your mind, define nature as simply as you can. What is the world made of?
   If you answer something like, “earth, water, air and fire,” then you are thinking like the Greek philosopher Empedocles. In the 5th century BC, Empedocles proposed that all worldly substances were composed of these four elements. Aristotle based his own natural philosophy on this notion, theorising that the ratio of these elements in matter determined substance and form.
   It was not until two thousand years later that scientists began to believe otherwise. In 1776, Joseph Priestley of England discovered that water was made of two smaller elements. A few years later, his French colleague, Antoine-Laurent Lavoisier, deduced that water’s “oxygen” – as Priestley termed it – was the active component of air. Lavoisier, considered the father of modern chemistry, offered theories of oxygen’s role in combustion and respiration, and invented a new terminology to suggest a logic of chemical reactions.

Finding the invisible
In the many decades that followed, scientists discovered more of the invisible in nature – all the way down to electrons, photons, muons and quarks – proposing new theories and expanding the base of modern natural science and physics.
   The first discoveries propelled the Industrial Revolution and formed the foundation for modern industry. From the steam locomotives of the early 1800s to Nicolaus August Otto’s four-piston, internal combustion engine in 1876 to Thomas Edison’s incandescent lamp in 1879, the world became mobile and electrified.
   The world was changing. The original respect for balance in nature – the holistic interaction of the four elements – was forgotten as science and industry homed in on ways to move society ahead. Miners and drillers extracted coal and oil from the earth to fuel engines and power plants, which in turn carried goods, people and electricity over new networks of railways, highways, seaways and power grids.
   Skies were hazy from combustion; the countryside was bulldozed as cities and endless suburbs crept outward. Rivers and lakes were polluted with solid wastes and chemical sludge.
   At the start of the 20th century, physicists like Albert Einstein, Niels Bohr and Max Planck debated the theories of quantum mechanics, which probed the microscopic nature of matter and radiation, changing the way scientists saw the universe. On the one hand, it led to the development of new technologies, such as microelectronics. On the other hand, it pushed forward the dark side of science.
   Work with Einstein’s discovery of the relation between matter, light and energy, E=mc², led to developments so powerful, they could end wars – and, in a worst-case scenario, destroy the world. In the 1930s, machines were built that broke apart the nuclear cores of atoms, releasing incredible amounts of energy, and governments heavily funded scientists in a race to invent a weapon that could use this force. The massive effects of the result – the atomic bomb – both frightened and astonished scientists.

Ecological balance
And then nature began to make a comeback. In 1962, American biologist Rachel Carson wrote her famous book, Silent Spring, which attacked the haphazard use of pesticides and helped people understand nature’s delicate balance. On a wide scale, the book pushed the Western World to grasp the concept of ecological disaster.
   Other warnings came from nature itself: erosion and deforestation, dwindling of animal and plant species, lack of pure water, rivers and fjords declared dead from pollution and poor agricultural practices. Acid rain fell, formed in the atmosphere from emissions of sulphur and nitrogen oxide. The world was also heating up, scientists warned, because of the exhaust from automobiles and factories that contained carbon dioxide and other greenhouse gases.
   In 1992, science couldn’t have made a more direct appeal. “Human beings and the natural world are on a collision course,” began an ominous letter called World Scientists’ Warning to Humanity, signed by 1,700 of the world’s scientists, spearheaded by the Union of Concerned Scientists.
   “The environment is suffering critical stress…. Our massive tampering with the world’s interdependent web of life … could trigger widespread adverse effects, including unpredictable collapses of critical biological systems whose interactions and dynamics we only imperfectly understand.”
   The group suggested major reforms, one of which was to move away from fossil fuels to more benign, inexhaustible energy sources to cut greenhouse gas emissions and the pollution of air and water. They also pleaded for resource management, to prioritise efficient use of energy, water and other materials.

Cleaning up the act
The world, it seems, was listening. Renewable energy development has taken off in the last decade – particularly the wind power sector. By the end of 1998, more than 10,000 MW of electricity-generating wind turbines were operating. By 2005, the global installed capacity is expected to multiply to at least 58,000 MW, according to one market analyst.
   Meanwhile, the factories of the world are cleaning up their act, imposing new environmental certification standards on themselves and their suppliers. Corporate shareholders and citizens are demanding “greener” products and processes as a global trading market springs up for clean emissions credits. Big fossil fuel companies like Shell and BP are even starting to pour money into renewable energy research and development.
   To help save raw materials and cut down on the amount of landfill waste, recycling of metals, glass, paper and plastics has become nearly commonplace. Technologies such as heat pumps, low-energy appliances and “organic” building practices have also helped homeowners conserve energy.
   An awareness of nature has again taken centre stage, along with a respect for the power of the four elements. As American physicist Sue Ann Bowling writes, “Even today, earth, water, air, and fire are not bad symbols for the four states of matter – solid, liquid, gas, and plasma.
   Solid – the ground to walk on, a solid roof over our heads.
   Liquid – rain to grow crops, the solvents and lubricants that keep our civilisation moving. Gas – oxygen for our lungs, winds to keep us from suffocating in our own wastes. Plasma – the fiery sun, ultimate source of energy for all mankind.”
   Perhaps, she adds, we’re not so far removed from Empedocles after all.

Jack Jackson
   a journalist based in Århus, Denmark
   photos Henrik Bonnevier and IBL