WMO Statement on the Status of the Global Climate in 2004

Global Temperature in 2004 Fourth Warmest

Report

By: World Meteorological Organization (WMO)

Date: 2004

Source: "WMO Statement on the Status of the Global Climate in 2004: Global Temperature in 2004 Fourth Warmest." World Meteorological Organization, 2004.

About the Organization: Established in 1950, the World Meteorological Organization (WMO) became part of the United Nations in 1951. Its membership includes representatives from 187 countries and territories. Its purpose is to study and make recommendations on the state of the atmosphere, oceans, and climate.

INTRODUCTION

The idea that human activities can change the natural climate is not new. As far back as the early 1800s, Americans noticed that cutting down forests in a particular area seemed to lead to higher amounts of precipitation. In 1896, a Swedish scientist published the earliest known description of the "greenhouse effect," a theory describing how carbon dioxide released into the atmosphere might raise the planet's temperature. The theory initially garnered little interest.

Through the early and mid-twentieth century, scientists were able to do little more than speculate about the impact of human activities on the atmosphere. At some points during this period, scientists warned that dust and smog particles in the atmosphere were likely to lead to global cooling; at other times the predictions described an impending rise in global temperatures.

Not until the latter twentieth century did a consensus emerge among many climatologists that the actual trend was in fact upward, and the climate did actually appear to be warming. One major factor in this coalescence of opinion was the emergence of powerful computer models which could more accurately examine the available data and model the intricacies of atmospheric flow and change.

While consensus exists on the fact that the earth is warmer now than it was a century ago, disagreement continues about the causes of the change. Advocates of global warming theory note that temperatures have run consistently above average for the past twenty years. Further, eight of the ten hottest years on record have occurred since 1995, and global warming proponents argue that these numbers are a direct result of human activities.

Critics of global warming theories generally don't dispute the higher average temperatures, arguing instead that human activities are not the cause. These critics note that from the fourteenth to nineteenth centuries Europe was cold enough for festivals to be held on the frozen Thames river, suggesting that the world climate warmed noticeably prior to the twentieth century. They also observe that in any varying process such as temperature, some values will always lie above the average and some will lie below it, suggesting that the current warming is simply an aboveaverage period.

While debate continues about the causes of rising world temperatures, agencies such as the United Nations continue to monitor climate change and report their findings, urging action to control the release of greenhouse gases which are believed to worsen the problem.

PRIMARY SOURCE

WMO STATEMENT ON THE STATUS OF THE GLOBAL CLIMATE IN 2004:

GENEVA, 15 December (WMO)—The global mean surface temperature in 2004 is expected to be +0.44 °C above the 1961–1990 annual average (14°C), according to the records maintained by Members of the World Meteorological Organization (WMO). This value of 0.44°C places 2004 as the fourth warmest year in the temperature record since 1861 just behind 2003 (+0.49°C). However, 1998 remains the warmest year, when surface temperatures averaged +0.54°C above the same 30-year mean. The last 10 years (1995–2004), with the exception of 1996, are among the warmest 10 years on record.

Calculated separately for both hemispheres, surface temperatures in 2004 for the northern hemisphere (+0.60°C) are likely to be the fourth warmest and, for the southern hemisphere (+0.27°C), the fifth warmest in the instrumental record from 1861 to the present.

Globally, the land-surface air temperature anomaly for October 2004 was the warmest on record for a month of October. The blended land and sea-surface temperature (SST) value for the Arctic (north of 70 °N) in July and the land-surface air temperature value for Africa south of the Equator in July were the warmest on record for July. Significant positive annual regional temperature anomalies, notably across much of the land masses of central Asia, China, Alaska and western parts of the United States, as well as across major portions of the North Atlantic Ocean, contributed to the high global mean surface temperature ranking.

Over the 20^th century, the global surface temperature increased by more than 0.6 °C. The rate of change for the period since 1976 is roughly three times that for the past 100 years as a whole. In the northern hemisphere, the 1990s were the warmest decade with an average of 0.38 °C. The surface temperatures averaged over the recent five years (2000–2004) were, however, much higher (0.58 °C).

STRONG REGIONAL TEMPERATURE DIFFERENCES

During June and July, heatwaves with near-record temperatures affected southern Spain, Portugal, and Romania, with maximum temperatures reaching 40 °C. In Japan, extreme hot conditions persisted during the summer with record-breaking maximum temperatures. An exceptional heatwave affected much of eastern Australia during February, as maximum temperatures soared to 45 C in many areas. The spatial and temporal extent of the heatwave was greater than that of any other February heatwave on record. A prolonged severe heatwave across northern parts of India during the last week of March caused more than 100 fatalities.

In July, abnormally cold conditions in the high-altitude areas of the Andes in southern Peru reportedly killed 92 people. Cold weather since late December 2003 was blamed for as many as 600 deaths across South Asia. During January 2004, maximum and minimum temperatures were below normal by 6-10 °C across northern India and Bangladesh.

PROLONGED DROUGHT IN SOME REGIONS

Drought conditions continued to affect parts of eastern South Africa, Mozambique, Lesotho and Swaziland in early 2004. However, enhanced precipitation in the last half of the rainy season provided some benefit to crops in southern Africa. The March-May rainy season was shorter and drier than normal across parts of the Greater Horn of Africa, resulting in a continuation of multi-season drought in this region. Isolated regions in the southern sector and portions of Uganda experienced driest conditions on record since 1961. In Kenya, a premature end to the 2004 long rains exacerbated the drought resulting from several years of poor rainfall in many areas. Food production in Kenya was projected at approximately 40% below normal. In spite of abundant rainfall in 2004, multi-year drought conditions also continued in Somalia, threatening agriculture and food security in the region. In Eritrea, which was struggling from nearly four years of drought, poor rains during the March-May rains exacerbated drinking-water shortages.

In India, the 2004 seasonal rainfall during the summer (south-west) monsoon season (June-September) over the country as a whole was 13% below normal with 18% of the country experiencing moderate drought conditions. In Pakistan, poor rains in July and August aggravated the long-term drought conditions, which had prevailed since the boreal spring. In Afghanistan, drought conditions that had plagued the country for the past four years continued in 2004 due to poor precipitation in the March-April season. In southern China, dry conditions persisted from August to October, resulting in the worst drought there in the last 54 years.

Long-term hydrological drought continued to affect much of southern and eastern Australia, as a result of rainfall deficits experienced since the major drought event of 2002/2003. Moderate-to-severe drought conditions continued in some areas of the western United States for the fifth year in a row. Some relief was experienced during September and October, though long-term drought remains entrenched across much of the region. Due to above-normal summer temperatures and dry conditions, a record area was burned by wildfires in Alaska.

ABUNDANT RAINFALL AND FLOODING IN MANY OTHER REGIONS

Precipitation in 2004 was above average for the globe and 2004 was the wettest year since 2000. Wetter-than-average conditions prevailed in the southern and eastern United States, eastern Europe and parts of western Asia, Bangladesh, Japan and coastal Brazil.

The Asian summer monsoon during June-September brought heavy rain and flooding to parts of northern India, Nepal and Bangladesh, leaving millions stranded. Throughout India, Nepal and Bangladesh, some 1,800 deaths were blamed on flooding brought by heavy monsoon rains. Flooding in north-east India (the states of Assam and Bihar in particular) and Bangladesh was the worst in over a decade. In eastern and southern China, heavy rains during June and July produced severe flooding and landslides that affected more than 100 million people and were blamed for more than 1,000 deaths nationwide. Heavy monsoon rainfall during July and August produced flooding along several rivers in north-eastern and central Thailand. A significant low-pressure system brought record-breaking snowfalls in the Republic of Korea on 5 March, resulting in damage to agriculture worth more than US$ 500 million. In October, two typhoons and active frontal systems brought record-breaking heavy rainfall to Japan. Tokyo received a total amount of 780 mm precipitation in October, which is the largest monthly amount on record since 1876.

Mudslides and floods due to heavy rains across areas of Brazil during January and early February left tens of thousands of people homeless and resulted in 161 deaths. In January, Peru and Bolivia also experienced hailstorms, heavy rainfall and flooding, which killed at least 50 people.

In Haiti, torrential rainfall due to the passage of Hurricane Jeanne produced disastrous flooding that claimed some 3,000 lives. This disaster came in the wake of flooding and landslides that affected Haiti and the Dominican Republic in late May 2004, in which more than 2,000 people were killed and several thousand others were affected.

In the second half of November and beginning of December, three tropical storms and a tropical depression passed over southern and central parts of the Philippines, drenching the islands with several days of torrential rainfall and triggering catastrophic flash floods and landslides, which killed, according to reports, more than 1,100 people. Heavy rains from mid-January to March in areas of Angola produced flooding along the river system, which flows into neighbouring Zambia, Botswana and Namibia. Extensive flooding along the Zambezi River, the worst flooding since 1958, threatened more than 20,000 people in north-eastern Namibia and caused extensive damage to crops.

In Australia, parts of Tasmania, Queensland and New South Wales received unusually heavy rainfall in mid-January, which produced flooding and damage. Parts of the Northern Territory received the wettest rainy season on record. A series of strong storms during February produced heavy rainfall and damaging floods in southern parts of New Zealand's North Island….

SIGNIFICANCE

This 2004 WMO report provided an extensive portrait of weather activity around the globe. The report noted not only higher average temperatures worldwide, but wide variations in rainfall, with some regions experiencing flooding and others plagued with drought. The WMO report from 2005 echoed similar themes, with higher-than-average temperatures resulting in the second warmest year on record. 2005 also brought a record number of Atlantic hurricanes, which some scientists claim are due to higher ocean temperatures brought on by global warming.

FURTHER RESOURCES

Books

Burroughs, William J. Climate Change: A Multidisciplinary Approach. Cambridge, U.K.: Cambridge University Press, 2001.

Bailey, Ronald, ed. Global Warming and Other Eco Mythos: How the Environmental Movement Uses False Science to Scare Us to Death. New York: Prima Lifestyles, 2002.

Web sites

Weart, Spencer. "The Discovery of Global Warming." American Institute of Physics. 〈http://www.aip.org/history/climate/summary.htm〉 (accessed March 13, 2006).

"Global Warming—Climate: Uncertainties." U.S. Environmental Protection Agency. 〈http://yosemite.epa.gov/oar/globalwarming.nsf/content/climateuncertainties.html〉 (accessed March 13, 2006).

"About WMO." World Meteorological Organization. 〈http://www.wmo.ch/index-en.html〉 (accessed March 13, 2006).