causes of climate change Flashcards
what are sunspots? how do they cause climate change? how big of an impact do they have
• Sunspots are temporary phenomena on the surface of the Sun that appear as dark spots.
• lasts about 11 years on average.
• more sunspots means more solar activity so greater insolation reaching Earth, which can contribute to warming.
• the effect of sunspots on climate is relatively small compared to other factors, such as greenhouse gas emissions.
what are volcanic eruptions?
how do they cause climate change?
how big of an impact do they have? (give example)
• Volcanic eruptions happens when magma from beneath the Earth’s crust escapes to the surface, releasing ash, gas, and lava in the atmosphere
• Volcanic eruptions release ash and gases, especially sulfur dioxide, which can form sulfate aerosols, which reflect sunlight away from the Earth leading to a temporary cooling effect on the earth.
• the eruption of Mount Pinatubo in 1991 caused the temp to drop by around 0.5°c for around 2 years
• minimal impact because it’s relatively short term and temporary.
what are the milankovitch cycles ?
• The Milankovitch cycles are 3 changes in the Earth’s orbit and axial tilt that affect the distribution of solar energy received by the Earth.
• the three types are : Eccentricity, Axial tilt (obliquity) and Precession
what is eccentricity? how often does it occur? how significant is it?
• Eccentricity refers to the shape of the Earth’s orbit around the Sun, as it changes circular to more elliptical, affecting the distance of the earth and sun, thus influencing the amount of insolation the earth recieves.
•The cycle of eccentricity occurs over a period of about 100,000 years.
• limited significance as it’s one of many factors. it also occurs once over a long period of time, however it plays a key role in the mass balance of a glacial system and the intensity of glacials and interglacials.
what is axial tilt? how often does it occur? how significant is it
• Axial tilt or obliquity, refers to the angle of the Earth’s axis, which varies between about 21.5 degrees and 24.5 degrees
•over a cycle of approximately 41,000 years.
• greater tilt means hotter summers and colder winters. on the other hand, a lesser tilt leads to milder seasons.
• quite significant as it can influence the melting of ice and snow, precipitation patterns, and overall temperature changes. also plays a role in the natural cycles of glacial and interglacial periods,
what is precession?
how often does it occur?
how significant is it?
• Precession refers to the wobble in the Earth’s rotation, which affects how sunlight is distributed across the planet.
• it occurs approximately every 26,000 years.
• quite significant as it can influence the timing of the seasons and the intensity of insolation resulting in climactic variations , contributing to natural cycles of glacial and interglacial periods, contributing in the long-term climate patterns.
what is the evidence that milankovitch cycles are the primary driver of climate change?
-coral reefs in barbados from the past 160,000 years till now.
- a strong correlation between the timing of the interglacials and eccentricity cycles
what is aphelion
the position the earth is in when its furthest away from the sun
wht is perihelion
the position when the earth is closest to the sun
