Question

What would best explain why it has taken scientists so long to come to a consensus that greenhouse gas emissions from human activity is leading to climate change?

There is no proposed mechanism for how greenhouse gases would lead to climate change.

Because there are so many factors involved in climate, it has been difficult to rule out other possible causes.

There is no correlation between greenhouse gas emissions and climate change.

Scientists couldn't show that increased greenhouse gas emissions preceded rising global temperatures.

Answer 1

What do you think?

Answer 2

A?

Answer 3

Not quite.
What would be your next guess?

Answer 4

B?

Answer 5

That's correct.

Climate change can be due to many factors, so it has been hard to prove that greenhouse gasses are causing the climate to change.