Historical UK Sea Levels (Calculus warning)

Historical UK Sea Levels

Reblogged from Watts Up With That.

Guest Post by Willis Eschenbach

There’s a new study out that uses previously overlooked or obscure sea-level records to extend the UK sea-level record back to 1832. It provides an interesting look at the question of possible acceleration in sea level records. The study is called “Changes in mean sea level around Great Britain over the past 200 years“. The data is available in Appendix A of the study.

Here are their results:

Now, is there acceleration in this record? The problem with that question is that it is well-established that there are long-term cycles in the tides with periods of up to 50 years. Given that, what can we say about this record?

Well, it’s clear that there was a rapid acceleration in about 1890. It’s a good thing that people weren’t hyperventilating about the so-called “CLIMATE EMERGENCY!!!” back then, they’d have claimed that their case was totally proven …

But that 1890s acceleration only lasted a couple of decades. After that, the rise was approximately linear until 1950.

Then there was a slight deceleration until about 1980, and a slight acceleration since then.

The problem is that the alarmists will look at the record, cut it off so it begins in 1950, and then loudly proclaim that the UK record shows a dangerous acceleration of 0.045 mm/year per year. Which is mathematically 100% true, and as the graph above shows, in the larger world it is 100% false

At the the current rate of UK sea level rise, the total rise by 2100 will be 160 mm (6.3 inches). But with the false “sea level acceleration” added in, the rise would be more than twice that, 340 mm (13.4 inches).

So that’s the latest in the world of sea level … still no sign of any claimed long-term acceleration.

Now, I was going to leave it there. But for the math inclined, mathematically acceleration is what is called the “second derivative” of a dataset. So I thought I’d take a look at the year-by-year acceleration in the dataset above. Here’s that result:

Depending on the period that you choose, you can say that there is positive acceleration, negative acceleration (deceleration), or no acceleration in the historical UK sea level record.

In other words … the endless claims of long-term acceleration in the rate of sea-level rise are absolutely not visible in the UK historical record.

Me, I’m off to see the sea, to Bodega Bay, which is where my polling place is for today’s special election. The ocean is my long-time friend, it’s always good for my spirit. As Karen Blixen (whose pen name was Isak Dinesen) wrote, “The cure for anything is salt water: sweat, tears or the sea”.

Works for me.

Best regards to all,

w.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s