The Challenge of Natural Hazards: Paper 1 Section A: Climate Change

Question 1

Climate Constantly Changing in Quaternary Period

Answer 1

-Quartenary Period is the most recent geological time period, spanning from about 2.6mil years ago to today
-In the period before Quartenary the Earth’s climate was warmer and quite stable
-During Quartenary, global temperature has shifted between cold glacial periods that last for around 100,000 years and warmer interglacial periods that last for around 10,000 years
-Last glacial period ended around 15,000 years ago since which the climate has been warming

Question 2

What is Global Warming

Answer 2

The term used to describe the sharp rise in global temperatures over the last century. It’s a type of climate change

Question 3

Ice and Sediment Cores as Evidence

Answer 3

-Ice sheets are made of layers of ice, one layer formed per year
-Scientists drill into ice sheets to get long cores of ice
-By analysing gases trapped in layers, they can tell the temp each year
-Remains of organisms found in cores taken from ocean sediments can be analysed

Question 4

Temperature Records as Evidence

Answer 4

-Since 1850s, global temps have been measured accurately using thermometers, giving a reliable short term record of temp change
-Historical records like harvest dates can extend the record of climate change further back

Question 5

Pollen Analysis as Evidence

Answer 5

-Pollen from plants gets preserved in sediment
-Scientists can identify and date pollen to show which species were living at that time
-Scientists know the conditions that plants live in now, so preserved pollen from similar plants show climate conditions were similar

Question 6

Tree Rings as Evidence

Answer 6

-A tree forms a new ring per year
-Tree rings are thicker in warm, wet conditions
-Scientists take cores and count the rings to find the age of the tree
-Thickness shows what climate was like
-Reliable source of evidence of climate change for past 10,000 years

Question 7

Orbital Changes Causing Climate Change

Answer 7

-Orbital changes affect how much solar radiation the Earth recieves
-Stretch: Earth’s orbit varies from circular to elliptical (Eccentricity)
-Tilt: Earth’s axis is tilted at angle as it orbits the Sun
-Wobble: Earth’s axis wobbles like a spinning top (Precession)

Question 8

Volcanic Activity Causing Climate Change

Answer 8

-Major volcanic eruptions eject large quantities