Hurricanes Harvey, Irma, What next?

By now just about everybody on the planet will have heard of Hurricane Harvey, and we all feel deeply sympathetic to the people of Houston. This was a dreadful time for them, which raises the question, why did this happen? As the disaster abates, the words “Global Warming” keep coming up. Global warming did not cause that Hurricane, it did not cause it to land on Houston, and with one reservation, it almost certainly did not cause hurricanes to be more common. However, global warming would have made the ocean a little warmer than usual, and that will have increased the intensity of any hurricane that was generated, made it more expansive, and more powerful. While it might have been the most newsworthy event, it was by no means the worst event attributable to an effect of global warming.

Hurricanes and Typhoons are just local names for tropical cyclones, and they originate because the earth is a rotating sphere, and because surface temperatures are uneven, therefore in places air rises because it is warmer, and in other places it falls. In the former you get low pressure, while in the latter, high pressure, and because there are pressure differentials, air flows towards and away from these systems respectively. Air moving in the north-south directions has different velocities in the east-west directions because of the different rotational velocities, and this generates some circular air motion (the Coriolis force) the direction depending on whether the air is being sucked in or being pushed out. In the normal course of events this would generate modest circulation, which would affect nobody badly.

However, there is an additional aspect. When the circulation goes over water, it evaporates moisture, and when this is sucked upwards in a low pressure event, eventually the air gets colder and the water comes out as water droplets, which generate clouds, and if there is enough moisture, rain. Of course, this is somewhat oversimplified, especially in mid-latitudes where you get fronts, etc, to complicate matters as air at different temperatures starts to mix, but the above, while oversimplified, at least lets us see what happened with Harvey. The reason the tropical storms are so bad, when you get away from the equator so as to get some effect from the Coriolis effect, is that the warmer the water, the more moisture gets sucked up. Water has a rather high latent heat of evaporation, so when it condenses out, that energy has to go somewhere. The warmer air rises, generating lower pressures below, and hence more suction, which means more water sucked up, leading to even more air being sucked in, leading to the extremes of rotational kinetic energy that we see.

So, the warmer the water, the more energy is available to power stronger winds, and more rain comes down. Harvey was particularly bad because it stalled over Houston. Normally, tropical cyclones run out of strength as they cross land, because there is no further moisture to power them, but Harvey had half of itself over land, and half over the Gulf of Mexico, so it was able to keep itself going longer than you might expect. So the hurricane would have been a little stronger than without the global warming, it would have dropped much more rain than without the global warming, but its path greatly accentuated the damage. Irma will do the same wherever it hits.

What global warming will also do is increase the number of tropical cyclones around the world. That is simply because by increasing the surface temperatures of the seas, there is more energy available for a weather event, hence more of the systems that would normally just qualify as storms or cyclones get upgraded to the tropical cyclone status. Worse, they do not have to be in the tropics. In Wellington, where I live, this winter the Tasman was 1.5 degrees C hotter than usual for this time of the year, and when a resultant system somehow met some colder sub Antarctic air, we got a storm with wind speeds that qualified for a category 3 hurricane, with a lot of rain, but it was cold. So, what we can expect in the future is many more of these storms, and not just in the tropics. The storms do not need to be hot; they merely need to have been powered initially with warmer seawater.

I mentioned that Harvey was not the worst event. At the same time, the monsoon over parts of India and Bangla Desh, thanks to increased sea temperatures, gave record rainfall that put about half the country under water, thus probably wiping out a large fraction of the country’s crops. It also killed about twelve hundred people and severely affected the lives of forty-one million people. And Bangla Desh in one of the poorest countries on the planet. There may be a tendency to think Houston, being part of the richest country on the planet, will get over this, and it probably will, but these changing events are going to happen everywhere, and as with Bangla Desh, many places will not be able to cope easily. It is the richer countries that have to start doing things to control these disasters, if for no other reason than they are the only ones with the means to make an impact. We really need to work out how to deal with such events, because they will occur, but better still, we need to take real action to minimize the number that do happen, and that means really doing something about global warming. Those who deny its existence should be made to exchange positions with people in Bangla Desh

Trump and Climate Change

In his first week in office, President Trump has overturned President Obama’s stopping of two pipelines and has indicated a strong preference for further oil drilling. He has also denied that climate change is real. For me, this raises two issues. The first is, will President Trump’s denial of climate change, and his refusal to take action, make much difference to climate change? In my opinion, not in the usual sense, where everybody is calling for restraint on carbon dioxide emissions. The problem is sufficiently big that this will make only a minor difference. The action is a bit like the Captain of the Titanic finding two passengers had brought life jackets so he confiscates them and throws them overboard. The required action was to steer away from a field of icebergs, and the belief the ship was unsinkable was just plain ignorant, and in my opinion, the denial that we have to do something reasonably dramatic about climate change falls into the same category. The second issue is how does science work, and why is it so difficult to get the problem across? I am afraid the answer to this goes back to the education system, which does not explain science at all well. The problem with science for most people is that nature cares not a jot for what you feel. The net result is that opinions and feelings are ultimately irrelevant. You can deny all you like, but that will not change the consequences.

Science tries to put numbers to things, and it tries to locate critical findings, which are when the numbers show that alternative propsitions are wrong. It may be that only one observation is critical. Thus Newtonian mechanics was effectively replaced by Einstein’s relativity because it alone allowed the calculation of the orbital characteristics of Mercury. (Some might say Eddington’s observation of light bending around the sun during an eclipse, but Newton predicted that too. Einstein correctly predicted the bending would be twice that of Newton, but I think Newton’s prediction could be patched given Maxwell’s electrodynamics. For Newton’s theory, Mercury’s orbit was impossible to patch.)

So what about climate change? The key here is to find something with the fewest complicating factors, and that was done when Lyman et al. (Nature 465: 334-337, 2010) measured the power flows across ocean surfaces, and found there was a net input of approximately 0.6 W/m2. That is every square meter gets a net input of 0.6 Joules per second, averaged over the 24 hr period. Now this will obviously be approximate because they did not measure every square meter of ocean, but the significance is clear. The total input from the star is about 1300 W/m2 at noon, so when you allow for night, the fact that it falls away significantly as we get reasonably away from noon, and there are cloudy days, you will see that the heat retained is a non-trivial fraction of the input.

Let us see what that means for the net input. Over a year it becomes a little under 19 MJ for our square meter, and over the oceans, I make it about 6.8 x 1021 J. There is plenty of room for error there (hopefully not my arithmetic) but that is not the point. The planet is a big place, and that is really a lot of energy: about a million million times 1.6 tonnes of TNT.

That has been going on every year this century, and here is the problem: that net heat input will continue, even if we totally stopped burning carbon tomorrow, and the effects would gradually decay as the carbon we have burnt gradually weathers away. It would take over 300 years to return to where we were at the end of the 19th century. That indicates the size of the physical problem. The fact that so many people can deny a problem exists, with no better evidence than, “I don’t believe it,” is our current curse. The next problem is that just slowing down the production of CO2, and other greenhouse gases, is not going to solve it. This is a problem that has crept up on us because a planet is a rather large object. It has taken a long time for humanity’s efforts to make a significant increase to the world’s temperatures, but equally it will take a long time to stop the increase from continuing. Worse, one of the reasons the temperature increases have been modest is that a lot of this excess heat has gone into melting ice. Eight units of water at ten degrees centigrade will melt one unit of ice, and we end up with nine units of water at nought degrees Centigrade. The ice on the planet is a great restraint on temperature increases, but once the ice in contact with water has melted, temperatures may surge. If we want to retain our current environment and sea levels, we have some serious work to do, and denying the problem exists is a bad start.

Some After-effects of the Earthquake

One of the interesting things about sea life is that the niches are so crowded that sometimes life clings to one very specialist zone. One of my favourite examples was a seaweed that grew on the southwest face of rocks in a harbour in a band of about ten centimeters depth, and then only in a spot that was about twenty meters long! Yes, that was somewhat exceptional, but the principle applies broadly, if not so strictly. Kaikoura is a great place for finding crayfish (rock lobster), and is reflected by the name, and the coast was a great place for other diverse marine life, including seaweed. During the recent quake, the land rose two meters. The places where I described certain seaweeds as originating from in some of my scientific papers are now high and dry, so the descriptions are no longer helpful. But this land rising will also be a serious disruption to marine life in the near intertidal zone because when the life form wants to be a specific distance below sea-level at low king tide, a two meter lift completely alters much of the environment.

This gives an interesting view from the environmentalists: they decree that none of the recently exposed wild-life shall be harvested, and instead be left to die. I am far from convinced this makes sense. Thus paua (a version of abalone) are hemophiliac, and if cut they die. They cannot return to the sea, and they cannot be shifted. What is the point in leaving them rot? I have heard the explanation, the nutrients will go back to the sea, but that is nonsense from my point of view. Such nutrients will only benefit plant life that can absorb it more or less immediately, and the ocean currents take the rest away. Some of the greenies seem incapable of putting numbers to their thoughts. I once saw one criticism of an attempt at aquaculture state that a particular one-acre pool was going to pollute the Pacific Ocean by deoxygenating it. Leaving aside the wave action during storms, and that the aquaculture was for seaweed, the Pacific is so huge such a statement merely displays a total lack of ability at elementary mathematics.

Back to more standard difficulties. Apart from small segments, the land to the north of Kaikoura is a very narrow coastal strip leading to almost vertical hills that are several hundred meters high. To the south there is a little flat land, then the road has to cross some very torn terrain. The earthquake dropped enormous amounts of rock onto the roads, and it will take months to clear reasonable access and stabilize the hills. The town has too little land for a significant airport, and while it has a port for small vessels, large ones cannot be accommodated.

So our TV programs showed tourists being evacuated on a navy transport ship. These are designed to have smaller landing craft that can more or less go anywhere. The tourists were taken out and had to climb a rope ladder to get into a hatch, where they would settle in a fairly mammoth area. The comfort levels would be low, because the military aims to get things done, but not with excessive comfort, but they aim to be able to do things as near to under any circumstances as possible.

Then in another news clip my attention was drawn to a ship just offshore. That did not look like any of ours, and we saw sailors in uniforms that were not like ours, and that was because it wasn’t and they weren’t. This particular ship was from the US navy, that happened to be in the region, and it dropped other activities to offer what help it could. Apparently there were also ships from the Australian and Canadian navies helping. Thank you, US, Canadian and Australian navies. In a disaster like this, one of the great assets of the military is that they get things done, and they have expertise and skills that really help when survival becomes an issue. Meanwhile our army has managed to open some sort of goat track route to get survival equipment in as well. So far, only in their near “go anywhere” trucks.

Meanwhile, in Wellington, it appears a number of buildings are going to have to be demolished. One of the interesting statements about the building code is, it is not designed to ensure a building will survive a major quake and be able to be used thereafter; it is designed so that the building will have enough structural integrity that nobody is going to get killed during the quake. My guess is property investors who have focused on apartments in the Wellington CBD are going to be a bit nervous for a while.

All of which makes my problems look a bit on the pathetic side. As far as I can tell (and with my recent hip replacement I am not yet sufficiently mobile to check a lot) my house has survived more or less intact, my children’s properties are essentially undamaged, and nobody nearby has sustained serious damage. All in all, things have worked out well for us.

So, back to the more mundane. Somehow I have to work out how to promote my latest ebook, ‘Bot War which will be published on December 2. Interestingly, I see some think that under President Trump, the US is headed towards disaster. I don’t think so, but my novel does give an alternative reason why some of what Trump says should be avoided.