EUROPEAN HEAT WAVE

A. It was the summer, scientists now realise, when felt. We knew that summer 2003 was remarkable; global warming, at last, made itself unmistakably Britain experienced its record high temperature and continental Europe saw forest fires raging out of control, great rivers drying of a trickle and thousands of heat-related deaths. But just how remarkable it is only now becoming clean.

B. The three months of June, July and August were the warmest ever recorded in western and central Europe, with record national highs in Portugal, Germany and Switzerland as well as Britain. And they were the warmest by a very long way Over a great rectangular block of the earth stretching from west of Paris to northern Italy, taking in Switzerland and southern Germany, the average temperature for the summer months was 3.78°C above the long-term norm, said the Climatic Research Unit (CRU) of the University of East Anglia in Norwich, which is one of the world’s leading institutions for the monitoring and analysis of temperature records.

C. That excess might not seem a lot until you are aware of the context – but then you realise it is enormous. There is nothing like this in previous data, anywhere. It is considered so exceptional that Professor Phil Jones, the CRU’s director, is prepared to say openly – in a way few scientists have done before – that the 2003 extreme may be directly attributed, not to natural climate variability, but to global warming caused by human actions.

D. Meteorologists have hitherto contented themselves with the formula that recent high temperatures are consistent with predictions of climate. For the great block of the map – that stretching between 35-50N and 0-20E – the CRU has reliable temperature records dating back to 1781. Using as a baseline the average summer temperature recorded between 1961 and 1990, departures from the temperature norm, or ‘anomalies’: over the area as a whole can easily be plotted. As the graph shows, such as the variability of our climate that over the past 200 years, there have been at least half a dozen anomalies, in terms of excess temperature – the peaks on the graph denoting very hot years – approaching, or even exceeding, 20°C. But there has been nothing remotely like 2003 when the anomaly is nearly four degrees.

E. “This is quite remarkable,” Professor Jones told The Independent. “It’s very unusual in a statistical sense. If this series had a normal statistical distribution, you wouldn’t get this number. Their turn period “how often it could be expected to recur” would be something like one in a thousand years. If we look at an excess above the average of nearly four degrees, then perhaps nearly three degrees of that is natural variability, because we’ve seen that in past summers. But the final degree of it is likely to be due to global warming, caused by human actions.

F. The summer of 2003 has, in a sense, been one that climate scientists have long been expecting. Until now, the warming has been manifesting itself mainly in winters that have been less cold than in summers that have been much hotter. Last week, the United Nations predicted that winters were warming so quickly that winter sports would die out in Europe’s lower-level ski resorts. But sooner or later the unprecedentedly hot summer was bound to come, and this year it did.

G. One of the most dramatic features of the summer was the hot nights, especially in the first half of August. In Paris, the temperature never dropped below 230°C (73.40°F) at all between 7 and 14 August, and the city recorded its warmest-ever night on 11-12 August, when the mercury did not drop below 25.50°C (77.90°F). Germany recorded its warmest-ever night at Weinbiet in the Rhine valley with the lowest figure of 27.60°C (80.60°F) on 13 August, and similar record-breaking night-time temperatures were recorded in Switzerland and Italy.

H. The 15,000 excess deaths in France during August, compared with previous years, have been related to the high night-time temperatures. The number gradually increased during the first 12 days of the month, peaking at about 2,000 per day on the night of 12-13 August, then fell off dramatically after 14 August when the minimum temperatures fell by about 50C. The elderly was most affected, with a 70 per cent increase in mortality rate in those aged 75-94.

I. For Britain, the year as a whole is likely to be the warmest ever recorded, but despite the high-temperature record on 10 August, the summer itself – defined as the June, July and August period – still comes behind 1976 and 1955, when there were long periods of intense heat. At the moment, the year is on course to be the third-hottest ever in the global temperature record, which goes back to 1856, behind 1988 and 2002 but when all the records for October, November and December are collated, it might move into second place, Professor Jones said. The 10 hottest years in the record have all now occurred since 1990. Professor Jones is in no doubt about the astonishing nature of the European summer of 2003. “The temperatures recorded were out of all proportion to the previous record,” he said. “It was the warmest summer in the past 500 years and probably way beyond what it was enormously exceptional.”

J. His colleagues at the University of East Anglia’s Tyndall Centre for Climate Change Research are now planning a special study of it. “It was a summer that has not: been experienced before, either in terms of the temperature extremes that were reached, or the range and diversity of the impacts of the extreme heat,” said the centre’s executive director, Professor Mike Hulme. “It will certainly have left its mark on a number of countries, as to how they think and plan for climate change in the future, much as the 2000 floods have revolutionised the way the Government is thinking about flooding in the UK. “The 2003 heatwave will have similar repercussions across Europe.”

GLOBAL WARMING IN NEW ZEALAND

A. New Zealand is expected to warm by about 3°C over the next century. The northern polar regions will be more than 6°C warmer, while the large continents – also the largest centres of population – will be 4°C or warmer. In contrast, the Southern Ocean, which surrounds New Zealand, may warm by only 2°C. The sea will act as an air conditioner and in this aspect, New Zealand’s location is comparatively fortunate.

B. Any predictions are complicated by the variability of New Zealand’s climate. The annual temperature can fluctuate as much as 1°C above or below the long-term average. The early summer of 2006-7, for instance, was notably cool, thanks in part to the iceberg that drifted up the east coast. A few months later, warm water from the Tasman Sea helped make May 2007 unusually hot. These variables will continue unaffected so that, although the general pattern will be for rising temperatures, the warming trend may not be uniform.

C. The Ocean to the south of New Zealand will have one important effect. As the world warms, the great bank of west winds that circle Antarctica will become stronger. This has already been observed, and its impact on New Zealand is likely to be profound, stronger, more frequent west winds will bring increased, sometimes catastrophic rainfall to the west coast of the country and create drier conditions in some eastern regions that are already drought-prone. At the same time, the general warming will spread south.

D. Furthermore, in the drier regions, the average moisture deficit – that is, the difference between the amount of water in soils available to plants and the amount plants need for optimum growth – will increase. Soils could go into moisture deficit earlier in the growing season and the deficits could last longer into autumn than at present. What we think of today as a medium-severity drought could be an almost annual occurrence by the end of the century. One direct consequence of warmer – and shorter – winters will be a reduction in snow cover. The permanent snow line in the mountains will rise, while snow cover below this will be shorter-lived. The amount of snow that falls may actually increase, however, even in some northern centres, owing to the intensification of precipitation, Ski-field base stations may eventually have to be moved upwards to be within reach of the new snow line but there could still be plenty of the white stuff up there.

E. There will also be a marked impact on New Zealand’s glaciers. Over the last 100 years, the glaciers have been reduced by 35%, although since 1978 increased snowfall has offset the effect of warming. The latest studies conducted by the National Institute for Water and Atmospheric. Research (NIWA), however, suggests that by the end of the century, warming over the Southern Alps could be significantly greater than over the rest of the country.

F. Sea levels around New Zealand have risen by 25cm since the middle of the 9th century and by 7 cm since 1990. Predictions for the coming years cover a wide range, however, partly because of unknown rises resulting from the melting of the ice in the Arctic, Greenland and Antarctica. In addition, sea level at any given time is affected by many different factors, one of which is called storm surge. When a Coincides with a high tide along low lying coastal areas, this bulge raises the tide higher than normal, creating. Surge not unlike a slow-motion tsunami. Not only does a rise in sea level increase the potential for this sort of damage, but it also has less immediate impacts. The one potentially grave outcome is that groundwater systems may become contaminated with saltwater, spoiling them for the irrigation of farmland, which in turn could diminish crop harvests. Similarly, over time, estuaries may be enlarged by erosion as tidal influences reach further upstream, altering the contours of whole shorelines and initiating further unforeseen consequences.

G. The impacts these changes will have on New Zealand are difficult to generalize. Human systems are better able to adapt to change than natural ecosystems because humans can see a problem coming and plan a response. Farmers and horticulturalists have made considerable advances, replacing crops they grow to better suit the new conditions. However, plant breeders will need to show considerable ingenuity if they can overcome the acute water shortages that are forecast.

H. For natural ecosystems the rate of change is crucial. If it is low, the plants and animals and fish will be able to ‘keep up’; if it is high, only the most adaptable species-those that can survive in the widest range of ecological niches-are likely to survive. Species adapted to only a narrow range of conditions or food sources will find adaptation much more difficult. Take tuatara, for instance. Their sex is determined by the temperature at which the eggs are incubated in warm (currently above 22 °C) condition and become predominately male – and now males already outnumber females by nearly two to one in some island refuges. In the mountains, as the permanent snow line moves upwards, the tolerance zones of some alpine plants and animals may simply disappear. It should also be remembered that global warming is just that – a global phenomenon. ‘New Zealand’s own greenhouse emissions are tiny – around 0.5% of the global total. Even if New Zealanders were to achieve the government’s target of carbon neutrality, this would have no discernable impact on global climate change.

I. The changes that global warming is going to bring to New Zealand during the 21st century are going to be significant, but where the country is likely to be most vulnerable is with respect to climate change elsewhere. New Zealand may warm more slowly than most places, but if its major export markets undergo damaging change, the economic impact will be severe.