Seven Models Guessed 2040. All Said Warmer. None Said The Same.

A climate model is a very big program that tries to work out what the air will do.

There is not one of them. There are lots, built by different teams in different countries.

I asked 7 of them the same question about 16 cities.

The question was simple. How much warmer will it be in 2031 to 2050 than it was in 1991 to 2010?

They All Said Warmer

This part is not in doubt at all.

Every model warmed every city. All 111 answers.

The very coolest answer in the whole pile was still 0.03 degrees warmer.

So nobody here is arguing about which way it goes.

They Did Not Agree On How Much

The middle city warms 1.08 degrees.

But for one city, the highest model and the lowest model are 0.51 degrees apart.

That gap is about half the warming itself.

And for 3 of the 16 cities, the models disagree by more than the warming they are talking about.

Delhi Is The Strange One

Delhi looks calm if you only read the average. It warms 0.72 degrees, the least of all my cities.

Then you look underneath.

One model says 0.03 degrees. That is almost nothing over twenty years.

Another says 1.57 degrees.

So the calm average is hiding two very different futures. If I printed only the 0.72 I would be telling you the least useful thing I know.

Where Does Not Help As Much As You Would Think

The far north is meant to warm fastest. Everyone says so.

In my ten cities that barely shows.

New York sits at 40.7 degrees north and warms 1.76 degrees. Reykjavik sits way up at 64.2 degrees north and warms 1.12.

So the city much further north warms less.

The link between how far north a city is and how much it warms is only 0.4. That is weak. The models disagree with each other more than the map explains.

Hot Days Are Easier To Feel

Degrees are hard to picture. Days are not.

Manila gets 9.8 days a year over 35 degrees now. By 2031 to 2050 the models say 16.9 days.

But the models range from 7.2 days to 26.6 days for that one number.

That is not a rounding argument. That is a different summer.

Why I Did This

This site already has a page on Philippine weather. It compared two records of the weather that already happened, and they were 1.09 degrees apart on Manila.

Two goes at the past, a degree apart.

So when models of the future are half a degree apart, that is normal. It is not a scandal.

Three Things I Cannot Tell You

These are 7 models, not all of them. There are dozens more. A different handful would give a different gap.

These are 16 cities, picked to spread from cold to hot. It is not the world and I do not give a world number.

And a wide gap does not mean the models are useless. Every one of them says warmer. What a wide gap means is that one number from one model is the wrong thing to plan with. The range is the answer.