Question

Three scientists discuss the primary cause of a global cooling event that occurred millions of years ago.

Scientist 1
The cooling was caused by volcanic eruptions. Volcanic dust and sulfur dioxide gas ($SO_2$) were injected into the stratosphere. These aerosols reflected incoming solar radiation back into space, reducing global surface temperatures. The cooling caused a rapid growth in polar ice sheets, which increased the Earth's albedo (reflectivity) and led to further cooling.

Scientist 2
The cooling was caused by the rapid expansion of early forests. The growth of these plants absorbed large amounts of carbon dioxide ($CO_2$) from the atmosphere through photosynthesis. The reduction of this greenhouse gas decreased the atmosphere's ability to retain heat, leading to global cooling. Ocean temperatures dropped, which increased the amount of $CO_2$ that dissolved in the oceans, further lowering atmospheric levels.

Scientist 3
The cooling was caused by a large asteroid impact. The impact blasted massive quantities of pulverized rock and dust into the upper atmosphere, blocking sunlight for several years. This dust layer reflected solar radiation, preventing it from warming the surface. The lack of sunlight caused widespread plant die-offs and triggered a long-term cooling cycle as snow cover expanded.

Match each of the following statements with the specific scientists who would agree with that statement.