Climate Change: Evidence Flashcards
What Pollen evidence was found that supported the idea that our climate has changed?
Plant species have climatic requirements that affects their geographical distribution. They also have uniquely shaped pollen. If the pollen falls into an oxygen free environment then it is preserved for ever. If over time different types of pollen fall into different oxygen free environments in the same location then today we can see that the climate must have changed because different plants with contrasting climatic requirements are stationed in the same place therefore their needs/climatic requirements were matched at different time periods
What is the limitation of the pollen evidence that suggests climate change?
Pollen can travel great differences and end up accidentally in completely opposite climates
How does dendrochronology support climate change?
A year of warm and moist weather leads to rapid tree growth leaving a wide tree ring on the trunk. We can analyse the data of the tree trunks and estimate a trend of how climate was changing over the years of that tree growth.
What is the limitation to the dendrochronological evidence?
Trees respond more to moisture than TEMPREATURE
Where are the locations for most ice core analysis?
Greenland and Antarctica
How are ice cores analysed to prove climate change?
Bubbles in ice cores contain a number of gases such as CO2 and CH4. Scientists can analyse the gases in these cores and based upon knowledge of different isotopes can estimate the climate at the time.
How do the different oxygen isotopes prove climate change?
Oxygen 18 harder to evaporate and form ice because it’s heavier, therefore needs more warm conditions to evaporate. Where there is more of this oxygen in an ice core it suggests that the climate at the time of that part of glacier forming was warmer. It is the opposite process for oxygen 16. The two isotopes relation to each other is always about the same (1 O18 for every 500 O16)it’s just more of the O18 is used for glaciers formation in warmer climates, if it’s in glacier form then it can be taken out and recorded through ice cores
How does the use of carbon in photosynthesis help with proving climate change?
Plants use carbon in photosynthesis no matter which isotope it is. C12 doesn’t decay but C14 does at a known rate. Scientists from looking at the amount of C12 can say how much of C14 the plant used. They then have parts of an equation to say how long ago the plant had X amount (initial amount at point of death) of C14 (Initial amount, rate of decrease and current amount). Then from looking at that they can say how long ago the plant died. Then can use knowledge of that plant species climatic requirements of today to say what the climate was at the time of death.
What do species of the coloptera beetle prove about climate change?
They have many different species of which all have very specific climatic requirements. The fossil of a specific beetle can be dated and measured against knowledge of that species of today to say the climate of the earth at the time dated of the fossil beetle
How does sea level rise prove climate change?
The heating up oceans due to a warmer climate causes expansion this is known as eustatic change. This can lead to fjords and rias forming most notably in Norway. The records of these landforms in terms of sea level height can indicate an increase temperature of climate.
What evidence is there to say that ice cores are extremely accurate?
Since the 1960s the South Pole climate station has been recording the percentages of different gases in the atmosphere. An ice core was recently taken out the same area and the method used to measure the gases in the cores matched the nightly accurate data taken at the South Pole climate station suggesting that the ice cores are also accurate.
What is happening to the CO2 and CH4 levels of the atmosphere?
Since the industrial revolution ended in 1830 there has been an exponential increase in the amount of CO2 and CH4 in the atmosphere. In the 20th century it started to really pick up, and now it’s rate of increase is unparalleled. Before all this there was a very stable amount of these gases in the atmosphere.
What is the link between CO2 and CH4 with temperature? What does it mean?
Over the last 800,00 years they have matched each other’s correlation, suggesting that now with this unprecedented sharp increase in these gases temperature will follow - that’s global warming.
