Climate change Flashcards
how has orbital theory made the Earth cooler?
due to the Earths orbit, the amount of solar radiation we receive is decreased
how does asteroid theory make the earth cooler?
when an asteroid hits the earth, the large impact creates ash and dust which then rises to block out the sunlight
how does sunspot theory make the earth warmer?
when the sunspots appear, it means the earth is giving out more solar radiation than usual, therefore warming the earth
how does volcanic eruption theory make the earth cooler?
gases from a volcanic eruption such a sulfur nitrate and ash rise into the atmosphere and block out sunlight
how do ice cores tell us that climate has changed over time?
ice at the bottom of the core can be thousands of years old and contain air bubbles from around that time. The amount of carbon dioxide in the air tells us how warm the climate was around that time (the more carbon dioxide, the warmer, the less, the colder)
how does dendrochronolgy tell us that climate has changed over time?
A tree grows a ring each year. Tree rings grow wider in good growing conditions (warm temps) and more narrow in bad growing conditions (colder temps), therefore we can tell what harvests were like in the past.
how do pollen grains tell us that climate has changed over the years?
Pollen grains are blown into water and preserved in sediment on the sea bed. Each pollen grain has its own shape depending on the plant it came from. This lets scientists know what type of plants were growing in the area at the time, therefore hinting the temperatures.
what is the enhanced greenhouse effect?
greenhouse gases are being used more often causing them to become stronger, speeding up the process of global warming.
what are greenhouse gases?
gases such as carbon dioxide, methane, nitrous oxide
what is global warming?
the process in which the earth is gradually becoming hotter due to greenhouse gases polluting the atmosphere
which human action produces carbon dioxide?
burning fossil fuels and deforestation
which human action produces methane?
agriculture, landfills and rice farming
which human action produces nitrous oxide?
vehicles (especially aeroplanes) and fertilizers used in agriculture
what % of global warming is due to carbon dioxide usage?
89%
what % of global warming is due to methane usage?
7%
