Humans? pic.twitter.com/FXJiZSwoem

— PDX_Info (@momma_pdx) August 2, 2024

The context here is that the reply is trying to say that climate change cannot be the cause of increasing severity of wild fires because 80% of the fires are caused by humans.

However, these are not mutually exclusive, as “PDX_Info” would like you to believe. Here’s why:

There are three types of causes:

• Sufficient – guarantees the effect.
• Necessary – required to trigger the effect (but does not guarantee the effect).
• Contributing – neither necessary nor sufficient, but makes the effect more likely.

Now that we have an understanding of causal relationships, let’s examine the increase in fire activity and what kinds of cause humans and climate change are.

The presence of humans does not guarantee a fire. So, it’s not a sufficient cause.
The presence of humans is not required for a fire, so it is not a necessary cause.
Humans do all sorts of things that make fires more likely, so we found it!
Humans are a contributing cause.

The presence of climate change does not guarantee a fire, so it is not a sufficient cause.
The presence of climate change is not required for a fire, so it is not a necessary cause.
Climate change makes fires more likely, so we found it!
Climate change is a contributing cause.

One important thing to know about contributing causes is that they never act alone.
In the case of fire activity, it is almost certainly true that both humans and climate change are contributing causes.

However, when it comes to increased fire activity, climate change clearly has a larger impact. We can demonstrate that its contributing effect is increasing over time.
The human cause is less clear. I have not seen the analysis over time, and it’s what’s needed to claim they are a cause.

The irony, of course, is that humans cause climate change, so they accidentally happen to be right. 😂