TASK DEFINITION: Read the passage and find if the passage agrees, disagrees, or has a neutral stance on whether Global warming is caused by human activities. Answer only with keyword (a) agrees - if passage agrees with the target (b) disagrees - if passage disagrees with the target (c) neutral - if the given passage neither agrees nor disagrees with the target. You don't need to use external knowledge in this task, and you have to answer based on the given passage.
PROBLEM: That level of warming, while potentially producing dire effects on agriculture, sea level and the natural world, might at least be tolerable.

SOLUTION: disagrees

PROBLEM: And ocean acidification, which comes from the added carbon absorbed by oceans, will harm marine life.

SOLUTION: agrees

PROBLEM: During the past 15 years, the retreat of summer sea ice has led to a 5 percent increase in the amount of energy the Arctic Ocean has taken up.

SOLUTION:
agrees