Query: I conclude that it must be ice accumulation, through evaporation of ocean water, and subsequent precipitation turning into ice.

Relevant passages:
Snow <=SEP=> Snow pertains to frozen crystalline water throughout its life cycle , starting when it precipitates from clouds and accumulates on surfaces , then metamorphoses in place , and ultimately melts , slides or sublimates away . Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air . Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets , which freeze in hexagonal-shaped crystals . Snowflakes take on a variety of shapes , basic among these are platelets , needles , columns and rime . As snow accumulates into a snowpack , it may blow into drifts . Over time , accumulated snow metamorphoses , by sintering , sublimation and freeze-thaw . Where the climate is cold enough for year-to-year accumulation , a glacier may form . Otherwise , snow typically melts seasonally , causing runoff into streams and rivers and recharging groundwater .   Major snow-prone areas include the polar regions , the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture and cold temperatures . In the Southern Hemisphere , snow is confined primarily to mountainous areas , apart from Antarctica .   Snow affects such human activities as transportation : creating the need for keeping roadways , wings , and windows clear ; agriculture : providing water to crops and safeguarding livestock ; such sports as skiing , snowboarding , snowmachine travel ; and warfare : impairing target acquisition , degrading the performance of combatants and materiel , and impeding mobility . Snow affects ecosystems , as well , by providing an insulating layer during winter under which plants and animals are able to survive the cold .

Sea level rise <=SEP=> A sea level rise is an increase in the volume of water in the world 's oceans , resulting in an increase in global mean sea level . Sea level rise is usually attributed to global climate change by thermal expansion of the water in the oceans and by melting of Ice sheets and glaciers on land . Melting of floating ice shelves or icebergs at sea raises sea levels only slightly .   Sea level rise at specific locations may be more or less than the global average . Local factors might include tectonic effects , subsidence of the land , tides , currents , storms , etc. .  Sea level rise is expected to continue for centuries . Because of the slow inertia , long response time for parts of the climate system , it has been estimated that we are already committed to a sea-level rise of approximately 2.3 m for each degree Celsius of temperature rise within the next 2,000 years . IPCC Summary for Policymakers , AR5 , 2014 , indicated that the global mean sea level rise will continue during the 21st century , very likely at a faster rate than observed from 1971 to 2010 . Projected rates and amounts vary . A January 2017 NOAA report suggests a range of GMSL rise of 0.3 -- 2.5 m possible during the 21st century .   Sea level rises can considerably influence human populations in coastal and island regions and natural environments like marine ecosystems .

Water <=SEP=> Water is a transparent and nearly colorless chemical substance that is the main constituent of Earth 's streams , lakes , and oceans , and the fluids of most living organisms . Its chemical formula is H2O , meaning that its molecule contains one oxygen and two hydrogen atoms , that are connected by covalent bonds . Water strictly refers to the liquid state of that substance , that prevails at standard ambient temperature and pressure ; but it often refers also to its solid state ( ice ) or its gaseous state ( steam or water vapor ) . It also occurs in nature as snow , glaciers , ice packs and icebergs , clouds , fog , dew , aquifers , and atmospheric humidity .   Water covers 71 % of the Earth 's surface . It is vital for all known forms of life . On Earth , 96.5 % of the planet 's crust water is found in seas and oceans , 1.7 % in groundwater , 1.7 % in glaciers and the ice caps of Antarctica and Greenland , a small fraction in other large water bodies , and 0.001 % in the air as vapor , clouds ( formed of ice and liquid water suspended in air ) , and precipitation . Only 2.5 % of this water is freshwater , and 98.8 % of that water is in ice ( excepting ice in clouds ) and groundwater . Less than 0.3 % of all freshwater is in rivers , lakes , and the atmosphere , and an even smaller amount of the Earth 's freshwater ( 0.003 % ) is contained within biological bodies and manufactured products . A greater quantity of water is found in the earth 's interior .   Water on Earth moves continually through the water cycle of evaporation and transpiration ( evapotranspiration ) , condensation , precipitation , and runoff , usually reaching the sea . Evaporation and transpiration contribute to the precipitation over land . Large amounts of water are also chemically combined or adsorbed in hydrated minerals .   Safe drinking water is essential to humans and other lifeforms even though it provides no calories or organic nutrients . Access to safe drinking water has improved over the last decades in almost every part of the world , but approximately one billion people still lack access to safe water and over 2.5 billion lack access to adequate sanitation . There is a clear correlation between access to safe water and gross domestic product per capita . However , some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability . A report , issued in November 2009 , suggests that by 2030 , in some developing regions of the world , water demand will exceed supply by 50 % .   Water plays an important role in the world economy . Approximately 70 % of the freshwater used by humans goes to agriculture . Fishing in salt and fresh water bodies is a major source of food for many parts of the world . Much of long-distance trade of commodities ( such as oil and natural gas ) and manufactured products is transported by boats through seas , rivers , lakes , and canals . Large quantities of water , ice , and steam are used for cooling and heating , in industry and homes . Water is an excellent solvent for a wide variety of chemical substances ; as such it is widely used in industrial processes , and in cooking and washing . Water is also central to many sports and other forms of entertainment , such as swimming , pleasure boating , boat racing , surfing , sport fishing , and diving .

Flood <=SEP=> A flood is an overflow of water that submerges land that is usually dry . The European Union ( EU ) Floods Directive defines a flood as a covering by water of land not normally covered by water . In the sense of `` flowing water '' , the word may also be applied to the inflow of the tide .   Flooding may occur as an overflow of water from water bodies , such as a river , lake , or ocean , in which the water overtops or breaks levees , resulting in some of that water escaping its usual boundaries , or it may occur due to an accumulation of rainwater on saturated ground in an areal flood . While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt , these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals .   Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel , particularly at bends or meanders in the waterway . Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers . While riverine flood damage can be eliminated by moving away from rivers and other bodies of water , people have traditionally lived and worked by rivers because the land is usually flat and fertile and because rivers provide easy travel and access to commerce and industry .   Some floods develop slowly , while others such as flash floods , can develop in just a few minutes and without visible signs of rain . Additionally , floods can be local , impacting a neighborhood or community , or very large , affecting entire river basins .