Query: Monsoons in China fail, the great rivers of Asia virtually dry up, and rainfall in central America falls by half.

Relevant passages:
Climate of Asia <=SEP=> The Climate of Asia is wet across southeast sections , and dry across much of the interior . Some of the largest daily temperature ranges on Earth occur in western sections of Asia . The monsoon circulation dominates across southern and eastern sections , due to the presence of the Himalayas forcing the formation of a thermal low which draws in moisture during the summer . Southwestern sections of the continent experience low relief as a result of the subtropical high pressure belt ; they are hot in the summer , warm to cool in winter , and may snow at higher altitudes . Siberia is one of the coldest places in the Northern Hemisphere , and can act as a source of arctic air masses for North America . The most active place on Earth for tropical cyclone activity lies northeast of the Philippines and south of Japan , and the phase of the El Niño-Southern Oscillation modulates where in Asia landfall is more likely to occur ,

Monsoon <=SEP=> Monsoon ( UK : -LSB- mɒnˈsuːn -RSB- US : -LSB- mɑːnˈsuːn -RSB- ) is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation , but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea . Usually , the term monsoon is used to refer to the rainy phase of a seasonally changing pattern , although technically there is also a dry phase . The term is sometimes incorrectly used for locally heavy but short-term rains , although these rains meet the dictionary definition of monsoon .   The major monsoon systems of the world consist of the West African and Asia-Australian monsoons . The inclusion of the North and South American monsoons with incomplete wind reversal has been debated .   The term was first used in English in British India ( now India , Bangladesh and Pakistan ) and neighbouring countries to refer to the big seasonal winds blowing from the Bay of Bengal and Arabian Sea in the southwest bringing heavy rainfall to the area .

Humid subtropical climate <=SEP=> A humid subtropical climate is a zone of climate characterised by hot and humid summers where tropical air masses dominate , and mild winters . These climates normally lie on the southeast side of all continents , generally between latitudes 25 ° and 40 ° and are adjacent to tropical climates to the south . While many subtropical climates tend to be located at coastal or near coastal locations . in some cases they extend inland , most notably in southern China and the southern United States .   Under the Köppen climate classification , Cfa and Cwa climates are described as mild temperate climates . This climate features mean temperatures in the coldest month between 0 ° C and 18 ° C and mean temperatures in the warmest month 22 ° C or higher . The Trewartha system was a 1966 update of the Köppen climate classification , and sought to redefine middle latitude climates into smaller zones ( the original Köppen system grouped all middle latitude climates into a single zone ) . Under the Trewartha climate classification , climates are termed humid subtropical when they have monthly mean air temperatures higher than 10 ° C ( 50 ° F ) for eight or more months a year and at least one month with mean temperature below 18 ° C ( 64.4 ° F ) . Normally , humid subtropical climates occupy the southernmost portions of the temperate zone from 23.5 to 35.0 north and south latitude .   Rainfall often shows a summer peak , especially where monsoons are well developed , as in Southeast Asia and Florida ( USA ) . Other areas have a more uniform or varying rainfall cycles . Most summer rainfall occurs during thunderstorms that build up due to the intense surface heating and strong subtropical sun angle . Weak tropical lows that move in from adjacent warm tropical oceans , as well as infrequent tropical storms often contribute to high sun ( summer ) seasonal rainfall peaks . Winter rainfall is often associated with large storms in the westerlies that have fronts that reach down into subtropical latitudes . However , many subtropical climates such as southeast Asia or Florida have very dry winters , with frequent brush fires and water shortages .

Desert <=SEP=> A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life . The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation . About one third of the land surface of the world is arid or semi-arid . This includes much of the polar regions where little precipitation occurs and which are sometimes called polar deserts or `` cold deserts '' . Deserts can be classified by the amount of precipitation that falls , by the temperature that prevails , by the causes of desertification or by their geographical location .   Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces . Although rain seldom occurs in deserts , there are occasional downpours that can result in flash floods . Rain falling on hot rocks can cause them to shatter and the resulting fragments and rubble strewn over the desert floor is further eroded by the wind . This picks up particles of sand and dust and wafts them aloft in sand or dust storms . Wind-blown sand grains striking any solid object in their path can abrade the surface . Rocks are smoothed down , and the wind sorts sand into uniform deposits . The grains end up as level sheets of sand or are piled high in billowing sand dunes . Other deserts are flat , stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones . These areas are known as desert pavements and little further erosion takes place . Other desert features include rock outcrops , exposed bedrock and clays once deposited by flowing water . Temporary lakes may form and salt pans may be left when waters evaporate . There may be underground sources of water in the form of springs and seepages from aquifers . Where these are found , oases can occur .   Plants and animals living in the desert need special adaptations to survive in the harsh environment . Plants tend to be tough and wiry with small or no leaves , water-resistant cuticles and often spines to deter herbivory . Some annual plants germinate , bloom and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture . Animals need to keep cool and find enough food and water to survive . Many are nocturnal and stay in the shade or underground during the heat of the day . They tend to be efficient at conserving water , extracting most of their needs from their food and concentrating their urine . Some animals remain in a state of dormancy for long periods , ready to become active again when the rare rains fall . They then reproduce rapidly while conditions are favorable before returning to dormancy .   People have struggled to live in deserts and the surrounding semi-arid lands for millennia . Nomads have moved their flocks and herds to wherever grazing is available and oases have provided opportunities for a more settled way of life . The cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification . Desert farming is possible with the aid of irrigation and the Imperial Valley in California provides an example of how previously barren land can be made productive by the import of water from an outside source . Many trade routes have been forged across deserts , especially across the Sahara Desert , and traditionally were used by caravans of camels carrying salt , gold , ivory and other goods . Large numbers of slaves were also taken northwards across the Sahara . Some mineral extraction also takes place in deserts and the uninterrupted sunlight gives potential for the capture of large quantities of solar energy .