Today in our geology lecture, we're discussing how volcanoes affect climate. When a volcano erupts, it releases ash and sulfur dioxide into the stratosphere. These particles can reflect sunlight back into space, which temporarily cools the Earth's surface. For example, the 1991 eruption of Mount Pinatubo in the Philippines lowered global temperatures by about 0.5 degrees Celsius for nearly two years. However, not all eruptions have this effect. Smaller eruptions that only reach the troposphere, like many in Iceland, have a minimal impact because the particles are quickly washed out by rain. So, the key factor is the height of the eruption column and the amount of sulfur dioxide released.
❓ Según la conferencia, ¿cuál es la razón principal por la que algunas erupciones volcánicas enfrían significativamente la superficie de la Tierra?
A. A. Liberan grandes cantidades de ceniza a la troposfera.
B. B. Expulsan dióxido de azufre a la estratosfera, reflejando la luz solar.
C. C. Provocan lluvias intensas que arrastran las partículas.
D. D. Ocurren en regiones tropicales como Filipinas.
✅ 正确答案
B. They eject sulfur dioxide into the stratosphere, reflecting sunlight.