Unit 1 Our Natural World Topic 2 Changing Climate

how has climate changed from the quaternary period to today?

durng the quaternary period to now the fluctuations in temparature have been increasing and the lowest temparature was at -2 degrees at the start of the quaternary period . now the lowest is at -8

evidence for climate change -geological

the discovery of 60 million years old croccodiles in north dakota suggests that the climate of the past is much warmer than it is today

elephant like mammals called mastodons were widespread across the usa during cold glacial periods. their thick coats allowed them to survive these temparatures. these fossil mastadons were found from alaska to florida, indicating that these cold periods extended across the whole of the usa

evidence for climate change -historical

ancient cave paintings found in france and spain of animals depict nature as it was 40,000 to 11,000 years ago this is a time when climate change was drastically changing. it was difficult to date these paintings

-records of extreme weather has been used to show us that in recent time extreme weather has become more common

-a study of bird nesting performed in the mid 1990s discovered that 65 species nested on average nine days earlier than they had in the 1970's which could be evidence of a warming world

-diaries and written observations also provide evidence of climate change but lakc accuracy

evidence for climate change -recent

-a map produced by nasa from 2008 to 2012 showed the global temparature anomalies for most of the world there was a warming trend which is consistent with maps produced over several decades.

-the shrinking of ice sheets and glaciers like the arctic sea declining in volume in the last 30 years and low level ski resorts in europe have suffered economic hardship due to increasingly unreliable snowfall

-in the past 100 years global sea level has risen between 10cm and 20cm

how do sunspots cause climate change?

the number of sunspots increases from a minimum toa maximum between the period of 11 years. this is called the sunspot cycle they are associated with strong magnetic fields which can cause solar flares and during the maunder minimum there were very few sunspots oserved which conincided with the coldest period during the little ice age

how do volcanic eruptions cause climate change?

volcanic eruptions blasts quantities of ash into the atmosphere which can block out the sun resulting in a decreased surface temparature. this is known as a volcanic winter. winds can also allow the ash to travel around the globe bringing along these cooling conditions

how do milankovitch cycles cause climate change?

the milankovitch cycles are cycles which closely relate to the earths orbit around the sun. scientists believe that these cycles afecct the timings and seasonality of the earths climate. in particular the 100,000 year eccentricity cycle from circular orbit to elliptical orbit coincides closelt with the alternation between cold glacial periods and warm interglacial periods in the quaternary period

how does the natural greenhouse effect work?

heat in the form of short wave solar radiation travels to reach the earths outer atmoshpere

-as it passes through the atmosphere some is absorbed by gases and liquids and some is reflected off the tops of the clouds

-radiation that reaches the earth warms up the surface

-the warmth is then released in the form of infrared radiation

-the heat is easily absorbed by water vapour and greenhouse gases like carbon dioxide methane and nitrous oxides.

- some of the heat can also escape into space

enhanced greenhouse effect-carbon dioxide

fossil fuel burning

deforestation(wood burning)

industrial processes(cement making)

enhanced greenhouse effect-methane

emitted from livestock and rice cultivation

decay of organic waste in landfill sites

enhanced greenhouse effect-nitrous oxides

vehicle exhausts

agriculture and industrial processes

how are humans enhancing the greenhouse gas effect overtime?

the natural greenhouse effect has become more effective in retaining infarred heat given of the earth because humans are buring fossil fuels ,deforestation is taking place , emmisions from cars have increased and all of this increases the amount of greenhouse gases which increasesthe absorbtion of ir heat

social impacts of climate change on the planet

600 million live in coastal areas less than 10 metres above the sea

migration due to people living in vulnerable areas

people might suffer from more floods and storm damage

jobs lost in ski resorts and fishing and tourism

enviromental refugee increase

economic impacts of climate change on the planet

multiple world citites could be impacted by flooding

valuable agricultural land may be lost to the sea or polluted by water

transport systems may be damadged

valuable land and property will need expensive coastal defence measures

countrues dependent of coastal tourism will be affected if those placed get flooded and people might not visit

enviromental impacts of climate change on the planet

fresh water sources could be polluted by sea water

damadge could occur to coastal ecosystems

coral reef damage by stroms and strong waves will affect fish breeding grounds and ecosystems

33 percent of coastal lands and wet lands could be lost in the next year

blocket harbours from sediment from coastal erosion

social impacts of climate change in the uk

elderly more vulnerable during heatwaves but will suffer less cold related deaths

summer heat increases tourism in the lake district

frequent flooding affecting houses farmland and infrastructure

economic impacts of climate change in the uk

teeside industries on coastal mudflats vulnerable to sea level rise

openeing of arctic navigation improving transport and trade within asian countries

cairngorms ski resorts may be forced to close

thames barrier needs replaced due to rising sea levels

enviromental impacts of climate change in the uk

earlier tree and plant flowering

new crops in southern england

droughts and water shortages in se england

vegetation and ecosystems move north

Precession

a natural wobble that occurs with earth like a spinning top. a copmplete wobble cycle cycle takes 26,000 years the earths wobble accounts for some regions expieriences very long days and nights in certain times of the year, such as northern norway

axial tilt

the earth spins on its axis to cause night and day currently the earth is tilted at 23.5 degrees however over a period of about 41,000 years it alternates from an axial tilt of 21.5 to 24.5 degrees. a greater degree of tilt is associated with a higher world average temparature

timescales for geologic,historical and recent climate change

geologic-last few 100,000 years

historical -last few thousand years

recent-last few decades

impact of climate change on tuvalu

-inreased level of salinisation which is pollution by saltwater from the sea level rise because of the expanding water particles due to global warming . this affescts soils having impact on agricultural productivity

-water supply issue due to drought as a result of climate change

- due to climate change resulting in storms and powerful tides coastal erosion has affected some of the islands eroding away productive land

-during king tides due to climate change powerful waves threaten homes and flood roads

what do icecores tell us about climate change

when snow falls in cold envirments itt builds up layer by layer scientists are able to drill into the ice to extract cylindrical cores from ice that is many thousands year old. by analysing the trapped water molecules from each layer of ice that can be dated accuratley scientists can calculate the temparature of the atmosphere of when the snow fell. the results of this research shows us the fluctuating temparatures of the glacial and interglacial temparatures

what do ocean sediments tell us about climate change ?

in deep ocean basins layers of sediment build up over thousands of years in a cold enviroment. scientists are able to drill deep into ocean sediments that are 5 million years old. by studying the oxygen isotopes trapped within these sediments it has been possible to calculate past atmospheric temparatures

What is the Little Ice Age?

a colder period that occured in northern europe starting in the 15th century until mid 19th century.