# Future prediction: if this happens… it will have… (future perfect tense)

Let's say global warming will hit its peak by 2020 (warmest earth). You want to say this in English, your prediction goes like this:

If global warming continues to the future, by 2020, it will have reached its peak, I believe.

This is only an estimation, meaning not sure. Am I correct to use "will have+participle" (present future) or should I use "would"? -using "would" may fit more as for the prediction thing is concern, BUT, from what I know, there is no such thing as "would have+participle" when you want to express something that will happen in the future. Right?

• Why do you want to use "would"? It implies a possible other outcome, which you don't have. For example, you could say "It would have reached its peak if people stopped driving cars." – user3169 Dec 28 '18 at 2:19
• What? I'd like to believe your sentence, but it seems illogical, have a look at yours. Also, your answer didn't answer my question, you just throw in another question to me. Sry man. – John Arvin Dec 28 '18 at 7:30
• Basically, you wrote "should I use would"? You should explain the reason why in your question. – user3169 Dec 28 '18 at 14:49
• I see, I've edited it just now. – John Arvin Dec 28 '18 at 16:50
• If GW continues, it will reach a peak in x. If GW continued, it would reach a peak in x. By the time GW has peaked, I will have kicked the bucket. :) – Lambie Dec 28 '18 at 21:40

To simplify a bit:

If global warming continues into the future, by 2020 it will have reached its peak.

will have is correct because the statement describes a period of time between now and 2020. So future perfect is the correct tense for this statement.
The result is certain, as long as the if condition is met. And there is no conflicting information regarding the "peak".

If you write:

If global warming continues into the future, by 2020 it would have reached its peak.

the problem is that would implies a possibility, so there needs to be both a "it happens" and "it doesn't happen". So adding a "it doesn't happen", you could write:

If global warming continues into the future, by 2020 it would have reached its peak. However, the prediction proved false after 5 volcanoes erupted in 2019.

• will have reached, though, is not present perfect....It's actually: future perfect....:) – Lambie Dec 28 '18 at 21:43
• Thx for the answer, one thing, why is that my preposition "to" is wrong and you've changed that into "into"? – John Arvin Dec 29 '18 at 10:05
• It's not wrong, just better. Think of "moving into the future" which indicates passage/movement, vs. "moving to the future" which doesn't. now --> future – user3169 Dec 29 '18 at 15:44