The line graph illustrates the percentage of people awared four problems as very serious in four countries from 2000 to 2010.
Overall, the portion of seriousness varies between the 4 issues, with shortages of fresh water accounts for the highest ratio. Moreover, this problem appears later than the others three problems.
Starting with automobile emisssions and climate change, these two issues reports the contrast trend in the period. Between 2000 and 2003, the two issues both saw a reduction by 3%. However, while the figure for climate change climbed up to 55% in 2010, that of automobile emission continued to slump to 45%, which is the lowest seriousness consideration in 2010.
Meanwhile, the percentage of people considered air polution and shortages of fresh water as very serious fluctuated throughout the period. In 2000 to 2003, the seriousness rate of air polution had the same trend as the two problems mentioned above, and it hit 60% in the end of the survey. In terms of shortages of fresh waters figures, despite its late appearance, it was always most problematic issues, with its figure fluctuated around 65% to 70%
