Climate change

Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as "global warming".

Scientists actively work to understand past and future climate by using observations and theoretical models. A climate record—extending deep into the Earth's past—has been assembled, and continues to be built up, based on geological evidence from borehole temperature profiles, cores removed from deep accumulations of ice, floral and faunal records, glacial and periglacial processes, stable-isotope and other analyses of sediment layers, and records of past sea levels. More recent data are provided by the instrumental record. General circulation models, based on the physical sciences, are often used in theoretical approaches to match past climate data, make future projections, and link causes and effects in climate change.

Arctic

The Arctic (/ˈɑːrktɪk/ or /ˈɑːrtɪk/) is a polar region located at the northernmost part of the Earth. The Arctic consists of the Arctic Ocean and parts of Alaska (United States), Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia, and Sweden. The Arctic region consists of a vast ocean with a seasonally varying ice cover, surrounded by treeless permafrost. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate limit of the midnight sun and the polar night. Alternatively, it can be defined as the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region.

Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, although by natural science definitions, much of this territory is considered subarctic. The Arctic region is a unique area among Earth's ecosystems. For example, the cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. In recent years, the extent of the sea ice has declined. Life in the Arctic includes organisms living in the ice, zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants and human societies.

Climate

Climate is the statistics (usually, mean or variability) of weather, usually over a 30-year interval. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate differs from weather, in that weather only describes the short-term conditions of these variables in a given region.

A region's climate is generated by the climate system, which has five components: atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere.

The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water bodies and their currents. Climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was Köppen climate classification originally developed by Wladimir Köppen. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and the potential effects on it of climate changes. The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region.

Change

Change, The Change, or Changing may refer to:

The process of becoming different

Ground zero

In terms of nuclear explosions and other large bombs, the term ground zero (sometimes also known as surface zero as distinguished from zero point) describes the point on the Earth's surface closest to a detonation. In the case of an explosion above the ground, ground zero refers to the point on the ground directly below the nuclear detonation and is sometimes called the hypocenter. Generally, it is also used in relation to earthquakes, epidemics, and other disasters to mark the point of the most severe damage or destruction.

Pearl Harbor

On December 7, 1941, the Empire of Japan carried out a surprise attack on Pearl Harbor, the headquarters of the United States Pacific Fleet in Honolulu, Hawaii. At the time of the attack, the U.S. and Japan were not officially at war and were still negotiating for a possible peace treaty. The event was described as ground zero due to the catastrophic damage inflicted upon the fleet and facilities within the naval base and other areas, as well as the nature surrounding the attack. The attack started at 7:55 am with 353 Japanese planes and lasted for 110 minutes. The most famous example of ground zero was Turret II of the USS Arizona, when an armor-piercing bomb penetrated through that turret towards the forward ammunition compartment which blew the ship apart and sunk it within seconds, killing 1,177 out of the 1,512 people on board. Hickam Field was also described as ground zero due to the devastation the Japanese caused to the airfield, killing 189 people and destroying many aircraft on the ground. In total, 2,467 people were killed in the attack, including 2,403 victims and 64 attackers, and eight battleships and 217 aircraft (including 19 from the attackers) were destroyed, making it the largest peacetime loss of life and property on American soil.