OCR B Geography GCSE Changing Climate

Climate change

changes in long-term temperature and precipitation patterns that can either be natural or linked to human activities

Quaternary period

the most recent geological period covering the last 2.6 million years, during which time there were several cold or warm periods

glacial periods

historic cold periods associated with the build-up of snow and ice and the growth of ice sheets and glaciers

inter-glacial periods

historic warm periods in-between glacial periods where conditions were much the same as they are today

global warming

a trend associated with climate change involving a warming trend (0.85°C since 1880)

Geological fossil evidence

plant and animal fossils provide a good indicator of what past climates were like.

ice core

a cylinder of ice drilled from an ice cap which contains a continuous record of past climatic conditions. It can be analysed to model past climate and help predict conditions in the future.

Ocean sediments

layers of sediment build up trapping evidence of past climates which can be drilled into and analysed to investigate past climatic conditions

The little ice age

a period between 1300-1870 during which winter temperatures were colder than today

Megafauna

large animals greater than 50kg e.g. giant beaver

Mastodons

an elephant like mammal with woolly coats

Milankovitch cycles

orbital variations (eccentricity, precession and tilt) which lead to natural climate change.

Eccentricity

100,000 year cycle during which the Earth's orbit changes from circular to elliptical and back to circular again. Colder periods occur when the orbit is more circular.

Precession

26,000 year cycle during which the 'wobble' of the Earth shifts

Axial tilt

a 41,000 year cycle during which the tilt of the earth cycles from 21.5 degrees to 24.5 degrees and back again

volcanic winter

colling trend caused by volcanic particules in the atmosphere blocking out some of the Sun's radiation

sunspot

a spot or dark patch that appears on the surface of the sunand is associated with an outburst of energy from the Sun.

sunspot cycle

a period lasting 11 years during which sunspot activity increases from a minimum to a maximum and then back to a minimum

greenhouse effect

natural warming of the atmosphere as heat given off from the Earth is absorbed by liquids and gasses, such as carbon dioxide

enhanced greenhouse effect

the increased greenhouse effect as a result of human activity

Sea level rise

an increase in sea levels attributed to increased amounts of water in oceans (due to less being stored on land in ice caps and glaciers) and thermal expansion of water

Thermal expansion

An increase in the volume of a substance when the temperature is increased