Regions across the world have been buffeted by extremes of weather, drought and floods. Sometimes an area is hit by one extreme, followed soon after by another, Niger being a case in point. In the case of floods in Pakistan, the Met Office says high pressure over Russia has forced the jet stream much further south than usual this year and this pattern has remained almost stationary over recent weeks. Therefore low pressure has been sitting over Pakistan longer than normal, intensifying the monsoon rains. "The extremes of rainfall are getting heavier and are entirely consistent with climate change predictions," said Helen Chivers, a spokeswoman with the Met Office.

Asia

In China rescuers used shovels and bare hands as they struggled today to save survivors of a major mudslide in the north-west, where blocked roads hindered vehicles trying to reach the disaster scene. At least 337 people were killed and 90 injured when landslides and flood waters engulfed Zhouqu county in Gansu province late on Saturday night. But with more than 1,100 people still missing, the death toll is likely to grow. Flooding across many provinces has killed more than 1,450 people this year and forced 12 million to flee their homes, but the Zhouqu landslide is the worst single incident. Experts had warned of the dangers of soil erosion in the area, known to be prone to mudslides. In spring south-western China was hit by drought, described as the worst in a century. In June south-east China, which had also endured drought, was hit by devastating floods. Southern China experiences flooding almost every summer, but the Beijing climate centre says extreme weather events have increased in recent years, with longer droughts and rain falling in more intense and damaging bursts. Pakistan's floods were caused by monsoon rains, described as the worst since 1929. The Pakistan meteorological department said that at one point 12 inches (300mm) of rain fell over a 36-hour period. Water levels in the river Indus, which cuts down the middle of Pakistan and has most of the population huddled around it, are said to be the highest in 110 years. The torrents, having ravaged the north-west, are now gushing deeper into Pakistan. The authorities have evacuated people living alongside expanding rivers as forecasts predicted further heavy rain that could worsen the country's flood crisis. The UN has raised its forecast of the number of people affected to six million and said the scale of the crisis was similar to the 2005 earthquake that hit northern Pakistan. About 1,600 people have died in the floods.

Africa

A severe drought is causing increasing hunger across the Eastern Sahel in west Africa, affecting 10 million people in four countries. In Niger, the worst-affected country, 7.1 million are hungry, with nearly half considered highly food insecure because of the loss of livestock and crops coupled with a surge in prices. Last year exceptionally heavy rainfall destroyed crops and devastated this year's harvest in the region. The resulting fall in production in staples like maize, millet and sorghum has affected much of West Africa's Sahel – fragile in the best of times – including neighbouring Chad and northern Nigeria.

Latin America

In April floods and mudslides struck the state of Rio de Janeiro, Brazil, after the heaviest downpours in four decades, leaving at least 212 people dead. The favelas, the shanty towns built on the hillsides of the city of Rio de Janeiro, were badly hit. Floods struck again in June, this time in the states of Alagoas and Pernambuco, over 1,200 miles north-east of Rio de Janeiro. At least 1,000 people were unaccounted for.

Europe

Southern Poland suffered its worst flooding in decades in May after heavy rains engorged rivers sending torrents of water through Bogatynia in south-west Poland and Görlitz in eastern Germany. The UK experienced the driest first six months of the year since 1929, which led to the imposition of a hosepipe ban covering 6.5 million people in north-west England. Russia experienced generally dry and hot weather starting around late May. Temperatures of 35C (95F) first occurred after 12 June, which alone was abnormal for the country, as average mid-June temperatures seldom rise above 30C ). Moscow and St Petersburg both recorded temperatures as high as 42C on 3, 4 and 5 July. Average temperatures in the region increased to over 35C. In early August, President Dmitry Medvedev declared a state of emergency in seven regions as firefighters struggled to contain about 600 blazes covering an estimated 309,000 acres (125,000 hectares).