Thoughts filed in: Geography

Sea level rise is gonna get a whole lot realer

1 Jan 2025

I was alarmed to recently learn that plenty of folks out there on the interwebz don't believe that the seas have risen, at all, for several centuries. Although, in hindsight, I shouldn't be surprised: after all, there's no shortage of climate change deniers out there, and sea level rise is very (although not completely) interconnected with climate change.

To be fair to those folks, it's true that – as they claim – the water level of various landmarks around the world, such as the Statue of Liberty, Plymouth Rock, and (in my own stomping ground of Sydney Harbour) Fort Denison, has not "visibly" risen since they were erected.

The fact, per the consensus of reputable scientists, is that the global average sea level has risen by 15-25cm (6-10") since 1900. Now, I'm willing to entertain the notion that, alright, for all practical purposes, that's not much. And that's just the average. So I consider it not unreasonable to concede that there are numerous places in the world today, where the sea level has barely, if at all, risen.

But.

The thing is, sea level rise lags behind global warming by several decades. So (if you'll excuse my hitting-rather-close-to-home choice of pun), what we've seen so far is just the tip of the iceberg. We've already locked in another 10-25cm (4-10") of sea level rise between now and 2050. And we're currently looking at a minimum 28-61cm (11-24") of sea level rise between now and 2100, and a minimum 40-95cm (16-38") of sea level rise between now and 2200. And those are the best-case scenarios, based: on the most conservative of scientists' conclusions; and on the world taking drastic action to reduce greenhouse gas emissions starting right now (a depressingly unlikely occurrence).

So, ok, perhaps sea level rise ain't gotten real yet for most people (although it sure has for some people). But I got news for y'all: it's gonna get a whole lot realer.

Ten rival national top cities of the world

9 Dec 2016

Most countries have one city which is clearly top of the pops. In particular, one city (which may not necessarily be the national capital) is usually the largest population centre and the main economic powerhouse of a given country. Humbly presented here is a quick and not-overly-scientific list of ten countries that are an exception to this rule. That is, countries where two cities (or more!) vie neck-and-neck for the coveted top spot.

Note: all population statistics are the latest numbers on relevant country- or city-level Wikipedia pages, as of writing, and all are for the cities' metropolitan area or closest available equivalent.

Where is the official centre of Sydney?

28 Mar 2016

There are several different ways of commonly identifying the "official centre point" of a city. However, there's little international consensus as to the definition of such a point, and in many countries and cities the definition is quite vague.

Most reliable and most common, is to declare a Kilometre Zero marker as a city's (and often a region's or even a country's) official centre. Also popular is the use of a central post office for this purpose. Other traditional centre points include a city's cathedral, its main railway station, its main clock tower (which may be atop the post office / cathedral / railway station), its tallest building, its central square, its seat of government, its main park, its most famous tourist landmark, or the historical spot at which the city was founded.

My home town of Sydney, Australia, is one of a number of cities worldwide that boasts most of the above landmarks, but all in different locations, and without any mandated rule as to which of them constitutes the official city centre. So, where exactly in Sydney does X mark the spot?