Weather, Climate And Ecosystems Flashcards
(118 cards)
What is the evidence for climate change ?
-during the last 2.6 million years the earth has naturally gone through periods of warming (interglacial) and cooling (ice age)
-since the last ice age earths surface temp has been stable at 14 degrees
-only since industrialisation has the temp of earth started to rise
-1970-2010 earths surface temp risen from 0.6 degrees- known as global warming
Causes of climate change (natural)
-naturally earths climate fluctuates from cool to warm
-the earths climate- Milankovitch suggests earth naturally wobbles (every 26,000 years) as it moves around sun. Affects the overall tilt of earth and amount of energy it receives from sun.
-solar sunsets- dark patches, sunspots cause greater radiation increasing the earth temperature
-volcanic activity- volcanoes can emit ash and sulphur dioxide into the atmosphere which can scatter sunlight back into space and reduces the earths temperature
Causes of climate change (human activity)
-deforestation- reduces carbon stores on earth and tress are also burnt releasing CO2 into the atmosphere
-industrialisation- factories burn fossil fuels and release CO2 etc. into air in large quantities
-transport changes- planes and boats transport goods and people around the world and car ownership has increased. This increases the release of greenhouse gases into the air as fossil fuels are burnt
-rice fields, cattle farming and waste dumps- add methane into the air
How do volcanic eruptions affect climate ?
-volcanic activity is a natural cause of climate change
-dust and sulphur dioxide are emitted into the atmosphere
-the mixture of dust and sulphur dioxide form an aerosol of tiny droplets that reflect the sunlight back into space
-this reduces the amount of solar energy reaching earth causing a cooling affect
-in 1992 an eruption in the Philippines caused 10% of sunlight reaching earth to be blocked out and the temperature dropped by 0.5 degrees for 2 years
Whats the carbon cycle ?
-human activities have disrupted it
-sunlight encourages photosynthesis
-plants respire and absorb co2
-leaves fall and then decay or are eaten by small decomposers
-animals eat plants and their waste releases carbon into soil
-plants absorb carbon from the soil
-fossil fuels also store carbon until it is released into air as co2 during burning
-trees are removed reducing carbon stores and when burnt they release carbon into the air
What is the carbon effect ?
-industrialisation causes greenhouse gas conc. to increase causing greenhouse effect
1- short term solar radiation enters atmosphere
2- much is absorbed but some is reflected as long wave solar radiation
3- greenhouse gases create a barrier and prevent most of the solar radiation from escaping our atmosphere
4- long wave radiation is reflected back to earth warming atmosphere at accelerated rate
What does climate mean ?
Average weather taken over a period of 30 years
What does weather mean ?
Day to day condition which changes constantly
What is the evidence for climate change ?
-scientist collecting co2 samples from Hawaii since 1958 (limited transport and industries means results should be quite fair)- results show it’s rising rapidly
-co2 samples have also been collected from Antarctica- climate data can be obtained from 420,000 years ago by drilling into ice to collect trapped air bubbles between layers of ice- since industrialisation levels have gone up
-evidence does show that earth goes through periods of warming and cooling
What’s the world’s circulation system ?
-warm air rises at the equator where sun is highest in sky and travels 30 degrees north where it cools and sinks before returning to tropics HADLEY CELL
-FERREL CELL found between Hadley and polar cells and lies between 60 degree north and 30 degree north (UK lays here)
-POLAR CELL is much smaller- cold air sinks at North Pole before flowing south at surface. Here it is warmed by contact with land ocean around 60 degree north where it rises
-at equator there’s an area of low pressure die to rising and expanding air. At around 30 degree north the sinking air creates area of high pressure
What is the climate like in high pressure zones ?
-calm stable and dry conditions
-hot weather increases evaporation and bakes soil so it can’t store water
-heat waves and droughts
What is a heatwave ?
-extended periods of hot weather
-usually happens when high pressure remains stationary over an area
What is drought ?
-lack of precipitation in an area over a long period of time
-Australia and South American have lots of droughts
-wild fires are common as land becomes dry and vegetation burns easily
What is a low pressure climate like ?
-causes tropical storms and monsoon rain
What causes seasonal differences in our climate ?
-throughout the earths orbit its on a tilt meaning that different areas experience different levels of sunlight throughout the year
-in our summer the ITCZ is in northern hemisphere where sun is nearer to the UK
-in the winter its in the southern hemisphere where its further away from UK
Whats the ITCZ ?
-where earths surface is the warmest
Whats the ocean conveyer belt system ?
-energy is moved from surplus to deficit
-warm currents transport water pole wards
-cold currents take colder water to lower latitudes
-oceans hold onto heat for longer than land does anf ocean currents move this heat around from tropics to higher altitudes
-in the uk the North Atlantic drift is a current of warm air that moves in a north east direction and maintains Britain’s warm temp climate
Why is it colder away from the equator ?
-due to curvature of the earth
-area closer to poles sun has a larger area of atmosphere to pass through and so more energy is lost and temperatures
-ice and snow nearer to poles causes the albedo effect
What’s the albedo effect ?
-snow reflects suns energy back into space making an area very cold
-without snow or ice suns energy is absorbed at the surface causing a higher temperature
How far is the UK north from the equator ?
Latitude of 50-58 degrees
How does altitude affect temperatures ?
-locations at higher altitudes have colder temperatures
-temp one degree colder for every 100 metres in altitude
What is a word to describe the UKs climate ?
Temperate
-cool wet winters and warm dry summers
-rarely any extreme hot or cold
How often does it rain in the UK ?
-On average once every three days
-highland areas in west receive most rain due to south west prevailing winds bringing moisture from the Atlantic Ocean
Where is it generally warmer in the uk ?
Further south
