TPO27 - Integrated TOEFL essay

In this set of material, the reading passage mentions three possible reasons for Little Ice Age that was a decline in the world's temperature and happened in many parts of the world. However, the lecturer finds all the ideas out of date and provides some evidence to support.

First of all, the reading passage claims that entering the melted glaciers into the ocean and disrupted the ocean currents which in turn, caused the Little Ice Age. In contrast, the lecturer states that now scientists know that Gulf Stream, most important and effective ocean current, only affects Europe and North America while the Little Ice Age happened in South hemisphere - including New Zealand and South Africa - as well. Therefore, changes in Gulf Stream cannot account for the phenomenon.

Furthermore, it is mentioned in the reading passage that volcanic eruptions caused huge amount of dust and dark clouds which prevented the entrance of sunlight, thereby happening Ice Age. On the contrary, the lecturer states that volcanic events can pose cool periods if the dust is enough to avert the sunlight reach to the ground but it should be noticed that this extent of darkness will have visual effects, such as sunset or grey or brown snowfalls, that people can notice it while no one reported such a big volcanic eruption. Hence, the second reason of the passage is not strong enough to explain the Ice Age.

Finally, the author of the passage declares that a reduction in the human population resulted in an increased growth of forests on fields that were not used for agriculture anymore. Conversely, the lecturer contends that there was not enough time for trees to grow and affect the climate in long-term after the human population decreased. As population increased again very quickly, the trees could not keep pace with it to absorb CO2 and reduce global warming.