Source: Revised GRE PDF 2nd Ed. Section 4; #13 (p. 68)

1

# The passage mentions which of the following

Computers cannot accurately predict climate change unless the mathematical equations fed into them adequately capture the natural meteorological processes they are intended to simulate. Moreover, there are processes that influence climate, such as modifications in land use, that scientists do not know how to simulate. The failure to incorporate such a process into a computer climate model can lead the model astray because a small initial effect can initiate a feedback cycle: a perturbation in one variable modifies a second variable, which in turn amplifies the original disturbance. An increase in temperature, for example, can boost the moisture content of the atmosphere, which then causes further warming because water vapor is a greenhouse gas. The passage mentions which of the following as adversely affecting the accuracy of computer predictions of climate change? Failure to allow for some of the processes that influence climate, Mathematical equations that do not accurately reflect natural phenomena, An overestimate of the role of feedback cycles

### 1 Explanation

1

Chris Lele

Sep 22, 2012 • Comment

Dweep Gogia

Can you explain how "A" is one of the answers? It's mentioned that scientists were not able to simulate the processes. How is that linked to "failure to allow for ..."?

Hi Dweep,

(A) says: Failure to allow for some of the processes that influence climate.

In other words, computer predictions of climate change are less accurate because they do not take into account some of the processes that influence climate.

This is supported here:

... there are processes that influence climate, such as modifications in land use, that scientists do not know how to simulate. The failure to incorporate such a process into a computer climate model can lead the model astray...

So, scientists cannot simulate these processes and thus scientists cannot put them in the computer model. Therefore the computer model doesn't account for these processes.

Dweep Gogia

Thanks for the explanation!

You're welcome!