Text 1 is an excerpt from The Secret Life of Dust by Hannah Holmes (Wiley). Text 2 is an excerpt adapted from the online article titled "Understand Climate Change" by the U.S. Global Change Research Program.

Text 1

One very clear message in the ice is that the Earth's climate is naturally erratic. According to the dust and gases trapped in the ice, the climate is always—always—in flux. If it's not getting warmer, it's getting colder. Year to year the shifts may be masked by an El Ni?o, La Ni?a, a Mount Pinatubo, or some other temporary drama.

Text 2

Earth's climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities. Global climate change has already resulted in a wide range of impacts across every region of the country and many sectors of the economy that are expected to grow in the coming decades. Thousands of studies conducted by researchers around the world have documented increases in temperature at Earth's surface, as well as in the atmosphere and oceans. Many other aspects of global climate are changing as well. Human activities, especially emissions of heat-trapping greenhouse gases from fossil fuel combustion, deforestation, and land-use change, are the primary driver of the climate changes observed in the industrial era.