F-5s are known in the American South as ‘The Wrath of God’. Tornadoes are the most violent storms on earth. They are classified accordind to the devastation they create and are measured on the Fujita scale with a maxima of F-5. An F-5 has a windspeed in excess of 415 kilometres per hour, and the highest wind speed recorded to date inside the funnel of a tornado is 528 kilmetres per hour. The damage caused by an F-5 is quite simply indescribable, resembling the aftermath of a nuclear war. A blade of straw has been known to pierce through a five centimetre thick board of wood in such winds.

From that night it seemed we were stalked by tornadoes as huge supercells formed across Arkansas, Kentucky,Tennessee, then east across Georgia and the Carolinas. The Weather Channel became compulsory viewing. Solid, low-built, block-like concrete motels took on an unexpected charm as tornadoes touched down with deadly regularity. We were in Waynesboro when the huge funnel of an F-4 touched down, missing us by a kilometre, but killing three people. Parts of the Blue Ridge Mountains, normally emerging into flowering forests of Cornus and wild cherry in spring, literally looked as if a nuclear explosion had blown them apart.

An ominous year of superstorms
1998 was known as the Year of the Superstorms ( Hurricane Mitch, a top-of-the-scale Category 5 came in the same year). That is until 1999. In 1999, an F-5 tornado that hit the southern suburbs of Oklahoma City was measured at 512 kilometres an hour. This slow moving storm supercell also brought a deadly series of tornado touchdowns to Texas and Tennessee. between May 3rd and May 6th. By June that year Tennessee, Kansas, and Texas were again making the headlines as another deadly series of tornadoes killed 40 people before moving west to devastate North Carolina and Georgia. These killer tornado seasons have continued every year since. Last year, the peak tornado season of March and April brought a massive deadly outbreak from Texas to Georgia, and May brought one of the worst outbreaks ever recorded with 80 touchdowns in eight states. The Midwest set a record for tornadoes.

Killer tornadoes and tornado clusters have always been known in the USA, but they are becoming more frequent. And they are moving into areas that were considered safe. At the end of March 2004, the first hurricane ever reported in the South Atlantic was swirling off the coast of Brazil. Hurricanes, also known as cyclones and typhoons , can only form over water that is 26.5 degrees C (80 degrees F) or warmer. In future, as the oceans warm, hurricanes will be created in places where they are previously unrecorded, and they will travel longer paths before making landfalls. Storm surges will occur in areas with no defences.

Climate change is here to stay
The International Panel for Climate Change (IPCC) is the world’s most respected authority on climate change. Its members have made the clearest case for climate change and its cause, and have declared that we are already involved in the process. In Australia, the CSIRO has produced climate models that confirm the trends modelled by the IPPC. The National Academy of Sciences has told the US Senate that climate warming is a real problem and getting worse. So has the National Oceanic and Atmospheric Administration (NOAA), the National Centre of Atmospheric Research, and the United States Environmental Protection Agency. In the UK, the Hadley Centre is at the forefront on climate warming research and has constantly warned of the worsening situation. The overwhelming concensus of the world’s leading climatologists is that climate change is both real and underway, and that it is caused by ever increasing levels greenhouse gases.

Yet somehow many still attribute climate warming to natural cycles, or to a concoction by extremist environmentalists to further their own agendas, or to the sensationalism of the media. Many accept the contrary opinions of various public figures who have no scientific training, let alone that of a highly specialised climate scientist. opinions of Others wash their hands of the problem imagining it to exist in the far future, or feel that the expense of acting is just too great.

The impossible equation for insurance companies
The world’s largest insurance companies have been among the first to realise that climate change is going to make a huge difference to our way of life. At windspeeds of around 190 kilometres per hour (120 miles per hour) homes begin to disintegrate with walls crumpling and roofs wrenching loose and flying away. Winds of this magnitude are expected to occur more often as just one aspect of climate change. The insurance industry, which is at the frontline of climate change, is closely monitoring weather related disasters worldwide.

The largest payouts have been in the United States where the number of weather related disasters have increased fivefold in the last three decades. That translates into five times the number of tornado touchdowns, hurricanes, storm surges, freak hailstorms, ice storms, floods, droughts, and wildfires. And despite better warning systems now in place it means huge damage to farms, wildlife, forests, businesses, and personal property. It also inevitably means increased loss of life.

Hurricane Hugo in 1989 was the first weather disaster in the world to break the one billion US dollars barrier in insurance claims. Three years later, in 1992, Hurricane Andrew broke all previous records, costing 15 billion US dollars. Eight large insurance companies went to the wall as a result. On a world scale, major weather catastrophes have jumped from 16 annually to 72 and the figure is rapidly climbing. After correcting for inflation, combined insurance payouts have increased from 9.3 billion Australian dollars in 1960 to in excess of 130 billion Australian dollars last year. Some of the world’s largest insurance companies are now warning that the costs of global warming related disasters are pushing up costs at the rate of 10% per year, and by 2065 these will be greater than the global GDP. Certainly with weather related costs increasing at 10% a year, they are increasing faster than the GDP of almost every country. In 2003, Munich Re which is one of the world’s greatest insurance firms, reported that insurance payouts had jumped 40% in the previous twelve months.

Global systems collapsing
It seems there is no longer any safe place to be. In 2003 , record heatwaves in Western Europe melted snows as never before and closed Mont Blanc to tourists. The Beaujolais and lavender harvests in France were a month early. It was considered the hottest summer in two millenia. And again we were there, occcupied with research, but inevitably part of the drama as tankers brought in water to villages, and streams sank to trickles and isolated pools through the gorges of Provence.The herb filled macquis vegetation blazed into runaway fires along parts of the Mediterranean coast, and farmers maintained anxious fire watches around the clock in the tinder dry mountain hinterland. It was just a taste of the runaway heat waves predicted for the future. In the end, the 2003 heatwave killed what was at first stated to be 3,000 people in France alone, a figure later adjusted upward to 15,000. The same heatwave also set record highs in Britain, Germany, Spain, and Italy, causing many further deaths. In total, it is believed that 35,000 deaths were caused in Europe by this heatwave. It was an appalling result for countries that had thought themselves very well able to care for their populations.

In 2006, record temperatures again seared Europe. Newspaper headlines we read in Provence had moved beyond fears for the annual lavender crop and survival of the farms drying with every day and at extreme risk of fire in some areas. Nuclear reactors were under threat of closure with inadequate water for their operational needs. The Spanish newspaper ‘El Semanal’ headlined “Europa Achicharrada’, meaning “Europe is Burned to a Crisp”. This time the death toll was small, although Paris and Berlin both registered 39 degrees C on July 20th, Belgium 37 degrees C on the previous day, and Wisley in England registered 36.5 degrees. This time Europe was better forewarned, and few elderly people in cities were left to cope alone with soaring temperatures as a large part of the population headed to the coast on annual vacations, thanks to health ministers in various countries. Heat warning systems were put in place, health advice for children and the elderly well disseminated, water rationed far more carefully, and man y sports banned during the hottest part of the day.

Few of these precautions are exercised in Australia, particularly those relating to heat exposure and to sports, although summers sre longer with more days than ever over 35 degrees C, and often in the 40+ degree range even close to the coast. Tennis competitors can face temperatures well over 50 degrees C on courts in December and January, risking serious health problems from dehydration and rising core temperatures.

Australia has been gripped by firestorms and an endless drought that has been described by climate scientists as the first climate change drought for Australia. Parts of the country have recorded the lowest rainfall since settlement began, and it is the also worst drought recorded since settlement began. The 2003-04 summer was brutal, registering extreme temperatures that continued well into autumn. Agricultural output was reduced by a reported 20%. The years 2005 and 2006 were equally extreme. Agricultural production continued to be cut by 20%. At the end of 2006, Victoria alone lost well over a million acres of fragile alpine region, forest, farms, and homes to bushfire. El Nino began to loosen its grip on the land in early 2007, but Australia is now in a pattern of back to back El Nino events and there is no guarrantee that respite for farmers will last for long. Among the CSIRO’s future predictions are summers with 50% more days over 35 degrees C. Even though the drought has broken in some areas, it continues over huge areas.

Complex global systems are collapsing. Twelve of the warmest years on record have occurred since 1990. The five warmest summers on record have occurred in the last seven years, 1997,1998, 2001, 2002, 2003, and 2006. Runaway climate is a genuinel weapon of mass destruction, striking anywhere without respect for any country and in many forms from tornadoes, floods, mudslides, massive storms, and devastating storm surges, to droughts and firestorms. Just how has climate change crept up so fast on us? Wasn’t it supposed to be a problem that was a comfortable century away?

The carbon bomb
The main cause of climate change has been the level of carbon dioxide pumped out into the atmosphere, so much that levels have risen by a third since the Industrial Revolution began in the 1760s. Incoming solar radiation is in part reflected back into space or absorbed by our atmosphere. But the balance of this incoming radiation heats the surface of the earth. The earth in turn reradiates energy back into space, almost all in the form of long wavelength infrared frequencies which can be trapped by both water vapour and carbon dioxide.

The result is that this trapped energy warms the lower part of the earth’s atmosphere called the troposphere. Some trapped energy finally exits into space but the balance finds its way back to the earth’s surface causing further warming. The higher the carbon dioxide levels, the higher the trapped heat levels. Without this ‘greenhouse effect’ the earth would not be able to support life, but now what was once a beneficial effect is being pushed into a genuine doomsday scenario by many human activities, most importantly the burning of fossil fuels which once formed the great living forests of previous geological ages. These forests, far past our modern imagining, had locked up carbon dioxide from the atmosphere of earth’s remote past by the process of photosynthesis.

Unfortunately carbon dioxide is not the only greenhouse gas. A number of other gases released by human activities can absorb infrared radiation and contribute to global warming including methane ( from microbial activity in animal guts, rice paddies, landfills, and the decomposition of vegetation excluded from air ), nitrous oxide ( released by the breakdown of nitrogenous fertilisers), chlorofluorocarbons (CFCs) and ozone. The commonest CFCs have around 10,000 times the greenhouse warming effect of carbon dioxide.

The latest predictions for our century
In August 2003, scientists at the Hadley Centre for Climate Change shocked the scientific community when they revised their prediction of a 5 degree rise in temperature during the 21st century upward to an unbelievable 8 degrees C. The CSIRO predictions released toward the end of 2003 were equally disastrous and in line with those of the Hadley Centre, a rise of 2 degrees C by 2030 and 6 degrees C by 2070. The 2007 climate predictions for Australia are devastating, confirming that the upper end of previous predictions will occur, with many more days of 35 degrees plus heat throughout the country, more frequent, longer, and more severe droughts, and the high probability of megafires.

Tripped by feedback loops
One of the reasons that the world’s leading climate modellers are reworking their predictions upwards is the existence of many feedback loops not factored in during earlier years of climate change modelling. These are causing knock on effects. As soils break down they will inevitably release 150 years of stored carbon according to the head of the climate prediction programme at the Hadley Centre, Geoff Jenkins.

Heat and drought are affecting forests, including the rainforests of Indonesia and the Amazon. As they dry out, they are becoming more vulnerable to immense forest fires that in turn pour the greenhouse gas carbon dioxide into the atmosphere. An unprecedented drought in 1997 in Indonesia saw an uncontrollable bushfire burn an area the size of South Korea and pollute the skies of neighbouring countries. This time we weren’t personally there on the ground, but we flew over that same hideous brown cloud for what seemed an eternity, watching the death of a once great rainforest. We were in the southern United States as several states were blanketed with the appalling dark smoke of the Amazon forest on fire thousands of miles south.

Some scientists hailed higher carbon dioxide levels in the atmosphere as a kind of ‘green fertiliser’ for the planet . As carbon dioxide levels rise, it is true that photosynthesis increases until it plateaus at 660 ppm. Perhaps this is an example of the narrow perspective of some of the scientific community and their failure to understand ecological systems. These same plants need water to grow, yet water will rapidly become the single most precious commodity on the planet in this century as increased evaporation rates dry out both soils and rivers. It is predicted that most of the wars of the 21st century will be water wars.

Worse, plants cannot adapt to the rapid change we are imposing on them. Already the very composition of the Amazon rainforests are changing. The Intergovernmental Panel on Climate Change (IPCC) has already raised the possibility that many of the earth’s forests, particularly those in the higher northern latitudes, will be unable to adapt and will die. There is already good evidence that this is happening. The World Wide Fund for Wildlife (WWF) considers climate change a grave risk for one third of the world’s forests. This has serious consequences for many plant and animal species. Sadly, that would also constitute another feedback loop as less vegetation will survive to store carbon dioxide through the process of photosynthesis.

Bodies of water around the planet hold reserves of dissolved carbon dioxide, and global warming will inevitably gradually release these reserves back into the atmosphere like the dissolved bubbles of carbon dioxide out of lemonade. Warming of the permafrost has set up yet another feedback loop resulting in the release of ever more significant amounts of trapped methane.

One of the most potent feedback loops occurs as the world’s ice melts. Ice and snow are very effective in reflecting solar radiation back into space but both land and water are far less effective. Sea ice has been monitored by NASA satellites for the last 20 years, and it has been shown that the Arctic is changing rapidly. Climate models have accurately predicted that the most marked early effects of climate change would appear at the poles. Ice cover in the Arctic is now the lowest observed. The thickness of the ice has shrunk 44% in the last 40 years.. Spring, summer, and autumn temperatures are rising, and it has been predicted that the Arctic could be navigable by water in the summer of 2006. Already entire Eskimo villages are being relocated to escape the erosion occurring in lower lying coastal areas as increasingly larger expanses of ocean build up wave strength. For the last twenty years, the North Atlantic Cycle has been arrested in a phase where low pressure over the Arctic is causing increased heat transport from middle latitudes. It may be partly natural, but there is no doubt that it is happening. The same warming is occurring in the Antarctic. There the glaciers are receeding The breeding grounds of all the Antarctic’s penguions is shifting southward. As the world’s ice melts we can expect to see an escalation in global warming.

Enter the new Ice Age?
For some time, an even more frightening scenario has been proposed by the scientific community, that of a rapid climate flip into a new ice age. We have become almost used to warnings from the scientific community that we are facing rising sea levels both from melting ice and the expansion in volume of oceans and seas with increasing temperatures, more intense and frequent storms and storm surges, more devastating droughts and floods, disastrous crop losses, and destroyed habitats. But paradoxically the most catastrophic result of greenhouse warming may be to flip us into a new ice age.

The prestigious Woods Hole Oceanographic Institution has postulated that we could soon, and very quickly, lurch into an ice age. It seems that our ocean-atmosphere system can be pushed to the point where it suddenly flips over, rather like a ship that has been holed and taking on water, gradually listing further and further, then quite suddenly rolling and sinking. Our climate record, even in the last 100,000 years, clearly indicates that extreme shifts have occurred in the world’s climate, often within less than a decade. It seems that human activities could be speeding up this cycle. The world is not the way so many imagine it to be, changing a little here and there, but largely remaining benign. Instead intensive research into ice cores and sediments reveal abrupt flips have been the rule, and they can occur in the middle of a warm period. The mechanism seems more and more to research scientists in the field to be caused by

A faltering Gulf Stream
Ocean currents are the driving force of our planetary climate system. In the North Atlantic, climate warming has in recent times been responsible for melting ice that has in turn caused a build-up of fresh water in the ocean. The Gulf Stream is like a giant river of salty water with a hundred times the flow of the Amazon, and it is warmed as it passes through the tropics. It flows along the coast of the eastern United States and south-easternCanada, then travels east to the shores of Ireland, the British Isles, and continental Europe. As it heads north, the salty Gulf Stream cools, becomes denser, and then sinks to great depths. As it sinks it pulls warm Gulf Stream water north.

The sinking of the Gulf Stream acts like a deep water pump that moves this huge current and in turn helps moves the entire interconnected global system of currents often referred to as the great ocean conveyor. Now the engine is under threat. If too much fresh water is added to the North Sea, the waters of the Gulf Stream become less salty and less dense, and they no longer sink quickly. The Gulf Stream stutters, and slows. Or fails to move north of southern Europe. Last year the Gulf Stream briefly stuttered. The well studied deep water pump between Scotland and Iceland has slowed by 20% in the last 50 years. Many abrupt climate changes in the past on our planet are believed to be due to a breakdown in the conveyor. At the end of the last Ice Age, the gradual melting of snow and ice diluting the northern Atlantic shut down the great ocean conveyor and plunged the earth into another frozen thirteen centuries. The Little Ice Age caused by a brief hiccup in the Gulf Stream at the beginning of the 16th century condemmed Europe, Russia, and North America to bitter, long winters for around 300 years.

A failure of the northernmost part of the Gulf Stream loop would condem most of modern Europe to a climate like that of Greenland. The Gulf Stream in normal mode keeps Europe between 5 and 9 degrees C warmer in the winter months than areas elsewhere in the world at comparable latitudes, and Western Europe’s sophisticated agriculture currently feeds 450 million people.

The Pentagon’s wild ride
The Pentagon released a paper in February this year entitled ‘An Abrupt Climate Change Scenario and Its Implications for United States National Security’. This time the weapons of mass destruction troubling the powers that be in the Pentagon were not those extraordinarily invisible weapons of Saddam Hussein but those of a far greater and infinitely more powerful enemy, nature. The Pentagon interviewed leading climate change scientists, carried out additional research, and modelled a varrety of scenarios with the assistance of these experts. They came up with plausible scenarios for the impact of an abrupt climate change similar to that envisaged by the scientists of Woods Hole. The study was certainly not based on optimistic outcomes, but neither was it a worst case scenario.

The two highly respected senior consultants involved portrayed a nightmare future of icebound and flooded countries, of shattered economies, wars that did not stop short of nuclear, of mass migrations, and of dwindling food and water resources. They described Europe with a climate approaching that of Siberia. The Pentagon study postulated that as early as 2007 a combination of melt waters and super storms in the Atlantic could breach the dike and seawall defences of the Netherlands allowing the sea to reclaim its own. At the same time, they envisaged higher tides and massive storm surges inundating low lying areas along the east coast of Canada, the eastern seaboard of the US and the Gulf Coast.

By 2020, the Pentagon scenario showed Africa in the grip of an unimaginable drought, Europe experiencing much colder weather, southern Europe struggling to fend off mass migration from a starving Africa, Scandiavia returned to a glacial deep freeze, India coping with massive southward migration of the people of Bangladesh displaced by storm surges and rising seas. China’s huge population made it vulnerable to loss of agricultural capacity in low lyiing coastal areas.

Kyoto - the end game
Runaway global warming is, as the Pentagon correctly identified, the most serious threat to us all in the 21st century, not terrorism. When the Kyoto Agreement was drawn up to limit greenhouse gas emissions into the atmosphere, it set out to annual global emissions have since risen 70%. The UK set a higher standard by agreeing to cut their emissions by 12.5 percent. The other members of the EU finally agreed to an 8 percent cut.

But the Kyoto agreement has not been ratified by Russia, or by the world’s biggest single polluter producing a quarter of the world’s total emissions, the United States, or by Australia which currently rates as the world’s greatest polluter on a per capita basis. Yet the latest calculations by the world’s leading climate scientists is that as a result of continuous failure to address this crisis and to reach an international agreement, unless we are to see even more dramatic rises than the 8 degrees C predicted by the Hadley Centre, all developed countries will now need to cut emissions by 80%. Nor can the less developed nations now be completely spared. The proposal currently under consideration would argue that every country without exception be allocated a fair proportion of the total emissions that can be safely emitted without further exascerbating global warming.

Gardening in a changing world
It would appear that you have been given the Chinese curse, ‘To live an interesting life’ , by being on the planet at this time. In face of such major possible changes, discussing the implications for gardeners seems such a minor aspect. Yet creating places of beauty and productivity will never be more important, just as they may well not have been so difficult for thousands of years. Among known problems are increased soil salination rates, and the migration of crop pests and diseases into areas where they were previously unknown. While the seed yield of grain crops is increased by increasing carbon dioxide levels, both protein quality and quantity are negatively affected. To compound this problem, the reduced maturation time resulting from increased growth rates also reduces the time for grain to accumulate nutrients. In many grain crops, at approximately 40 degrees C the spikelets of many grain species become sterile. Increased carbon dioxide levels have also been shown to upset flowering ratios in vulnerable crops such as the squash family and upset productivity.

Organic techniques will be very important to future gardens. Increased temperatures and deeper, longer droughts are forecast and the addition of large amounts of moisture retentive organic matter will be essential. Never will the tough old heirloom vegetables be more valuable. Their capacity to cope with extreme conditions is well known. They would never have lasted so long and been faithfully planted year after year if they were not so strong genetically and so dependable. They almost always bring with them the bonus of wonderful flavour and variety in colour, shape, and size. As the climate grows hotter and drier in some areas, plantings of ornamentals will need to be adjusted. At the moment succulents and cacti are gaining great popularity as drought resistant plants. But a garden of succulents is not necessary. Again the tough heirloom roses, perennials, climbers and annuals have survived.