Query: However, this is exactly what climate scientists have predicted for California since at least the 1980s: protracted periods of warm, dry conditions punctuated by intense wet spells, with more rain and less snow, causing both drought and floods.

Relevant passages:
Mediterranean climate <=SEP=> A Mediterranean climate -LSB- ˌmɛdɪtəˈreɪniən -RSB- or dry summer climate , is the climate typical of areas in the Mediterranean Basin . The Mediterranean climate is usually characterized by rainy winters and dry , warm to hot summers . While the climate receives its name from the Mediterranean Sea , an area where this climate is commonplace , it is also present in other areas of the planet , although with variations in the distribution of temperatures . In addition to the Mediterranean Basin , the climate is also found in most of California , in parts of Western and South Australia , in southwestern South Africa , sections of Western and Central Asia , and in Central Chile .   Outside of the Mediterranean Basin , the Mediterranean climate is usually located geographically on the western coasts of continental masses , typically between oceanic climates towards the poles , and semi-arid and arid climates towards the Equator . In essence , a Mediterranean climate is a combination of the three climates with winters somewhat mimicking winters in oceanic climates and summers imitating dry seasons in semi-arid and arid climates . Additionally , Mediterranean climates tend to be wetter poleward and drier the closer it gets to the Equator .   The resulting vegetation of Mediterranean climates are the garrigue in the Mediterranean Basin , the chaparral in California , the fynbos in South Africa and the Chilean scrubland in Chile . Areas with this climate are where the so-called `` Mediterranean trinity '' has traditionally developed : wheat , vine and olive . The latter is a tree that is only grown in areas that have this climatic pattern .

Rain <=SEP=> Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated -- that is , become heavy enough to fall under gravity . Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth . It provides suitable conditions for many types of ecosystems , as well as water for hydroelectric power plants and crop irrigation .   The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts . If enough moisture and upward motion is present , precipitation falls from convective clouds ( those with strong upward vertical motion ) such as cumulonimbus ( thunder clouds ) which can organize into narrow rainbands . In mountainous areas , heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains . On the leeward side of mountains , desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass . The movement of the monsoon trough , or intertropical convergence zone , brings rainy seasons to savannah climes .   The urban heat island effect leads to increased rainfall , both in amounts and intensity , downwind of cities . Global warming is also causing changes in the precipitation pattern globally , including wetter conditions across eastern North America and drier conditions in the tropics . Antarctica is the driest continent . The globally averaged annual precipitation over land is 715 mm , but over the whole Earth it is much higher at 990 mm . Climate classification systems such as the Köppen classification system use average annual rainfall to help differentiate between differing climate regimes . Rainfall is measured using rain gauges . Rainfall amounts can be estimated by weather radar .   Rain is also known or suspected on other planets , where it may be composed of methane , neon , sulfuric acid , or even iron rather than water .

Climate of the United Kingdom <=SEP=> The United Kingdom straddles the higher mid-latitudes between 49 ° and 61 ° N . It is on the western seaboard of Afro-Eurasia , the world 's largest land mass . These conditions allow convergence between moist maritime air and dry continental air . In this area , the large temperature variation creates atmospheric instability , and this is a major factor that influences the often unsettled weather the country experiences : where many types of weather can be experienced in a single day . In general the climate of the UK is cool and often cloudy , and hot temperatures are infrequent .   The climate in the United Kingdom is defined as a temperate oceanic climate , or Cfb on the Köppen climate classification system , a classification it shares with most of north-west Europe . Regional climates are influenced by the Atlantic Ocean and latitude . Northern Ireland , Wales and western parts of England and Scotland , being closest to the Atlantic Ocean , are generally the mildest , wettest and windiest regions of the UK , and temperature ranges here are seldom extreme . Eastern areas are drier , cooler , less windy and also experience the greatest daily and seasonal temperature variations . Northern areas are generally cooler , wetter and have slightly larger temperature ranges than southern areas .   Though the UK is mostly under the influence of the maritime tropical air mass from the south-west , different regions are more susceptible than others when different air masses affect the country : Northern Ireland and the west of Scotland are the most exposed to the maritime polar air mass which brings cool moist air ; the east of Scotland and north-east England are more exposed to the continental polar air mass which brings cold dry air ; the south and south-east of England are more exposed to the continental tropical air mass which brings warm dry air ( and consequently most of the time the warmest summer temperatures ) ; and Wales and south-west England are the most exposed to the maritime tropical air mass which brings warm moist air .   If the air masses are strong enough in their respective areas during the summer , there can sometimes be a large difference in temperature between the far north of Scotland ( including the Islands ) and south-east of England -- often a difference of 10 -- 15 ° C ( 18-27 ° F ) but sometimes of as much as 20 ° C ( 36 ° F ) or more . In the height of summer the Northern Isles could have temperatures around 15 ° C ( 59 ° F ) and areas around London could reach 30 ° C ( 86 ° F ) .

Effects of global warming <=SEP=> The effects of global warming are the environmental and social changes caused ( directly or indirectly ) by human emissions of greenhouse gases . There is a scientific consensus that climate change is occurring , and that human activities are the primary driver . Many impacts of climate change have already been observed , including glacier retreat , changes in the timing of seasonal events ( e.g. , earlier flowering of plants ) , and changes in agricultural productivity .   Future effects of climate change will vary depending on climate change policies and social development . The two main policies to address climate change are reducing human greenhouse gas emissions ( climate change mitigation ) and adapting to the impacts of climate change . Geoengineering is another policy option .   Near-term climate change policies could significantly affect long-term climate change impacts . Stringent mitigation policies might be able to limit global warming ( in 2100 ) to around 2 ° C or below , relative to pre-industrial levels . Without mitigation , increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 ° C. Higher magnitudes of global warming would be more difficult to adapt to , and would increase the risk of negative impacts .

Physical impacts of climate change <=SEP=> This article is about the physical impacts of climate change . For some of these physical impacts , their effect on social and economic systems are also described .   This article refers to reports produced by the IPCC . In their usage , `` climate change '' refers to a change in the state of the climate that can be identified by changes in the mean and/or variability of its properties , and that persists for extended periods , typically decades or longer ( IPCC , 2007d :30 ) . The climate change referred to may be due to natural causes and/or the result of human activity .