Friday, September 20, 2013

Ice, ice baby - Arctic sea ice and climate change

One of the clear signs that someone has an agenda is when they cherry pick the data. It’s a common mistake to focus too much on the short term at the expense of the longer view. A recent example of this is the cover of Arctic Sea ice. Skeptics are claiming that sea ice has undergone a recent recovery, and therefore, along with the apparent stalling of global warming as measured by atmospheric temperatures, climate change is a myth. This is simply not true.

Arctic sea ice loss has been steadily occurring for some time. Satellite observations show it has been in decline since 1979 when observations first began. Observations from the Danish Meteorological Institute and Norwegian Polar Institute and ocean vessels have shown sea-ice cover is much lower than it has been since 1870. Studies of older climate from tree rings, ice cores and lake sediments can take us back even further, showing sea-ice is at its lowest for over 1400 years.

Perhaps the best way to think about sea ice loss is to compare blocks of cheddar cheese to cheese slices. If you want to cut a slice off a slice of cheddar, you cut it length ways, with each slice of equal thickness. With each slice you cut off, the surface area of cheese decreases. Compare that to cheese slices. Each time you remove a slice, the surface area remains the same but the thickness of the cheese decreases.

The melting of sea ice is like the removal of cheese slices, except sea ice varies in thickness. The thickness of ice reflects its age, with the thinnest ice being last season’s freezing and the thickest being from multiple years of freezing. Each summer, sea ice thins due to warming temperatures. Consider a distribution of sea ice where 25% is less than one metre. If during a summer season, there is a total of one metre of thinning, then there will be a 25% reduction in total sea ice. If that distribution changes over time such that 50% has a thickness of one metre, then the same summer time melting reduces the area but 50% instead of 25%.

This is what has been observed over time, sea ice has thinned, or another way of describing it is that total ice volume has decreased, due to warming air and ocean temperatures. Over shorter timescales, individual weather events can dramatically affect the total surface area of ice as thin ice can rapidly grow. For example, in 2012, a low pressure system spent nearly two weeks churning up ice already thin from a warm start to the season resulted in the lowest sea ice cover on record, though scientists think the ice would have reached a record low anyway. This year’s so-called recovery simply means that low pressure systems have brought snow fall and not damaged the ice, resulting in the 6th lowest sea ice cover on record.

Image from Skeptical Science shows so called recovery is simply a growth in area due to seasonal differences.

The Great Arctic Cyclone of 2012

The moral of this story is that various key indicators of climate change do vary naturally on short time scales, be it year to year or over a few decades. This does nothing to change the longer term trends due to the burning of fossil fuels, land clearing and other drivers of climate change.

Further reading discusses the 2012 record low and the role the Great Arctic Cyclone played discusses the idea of tipping points and illustrates how sea ice varies from year to year. Moderately technical.

Monday, September 16, 2013

Making peace with lions

This short video from Ted is inspiring, that solutions for living alongside wildlife in an ever compressed world don't need to be hightech. All we need to do is think creatively so that we all might live in harmony. Now if only solving global warming were so simple....

Friday, September 13, 2013

Why top predators are essential to ecosystems

Talk by George Monbiot on his new book Feral on rewilding ecosystems. Book review to follow (when it arrives in the mail and I read it).

Monday, September 9, 2013

Democracy gone mad and the limits of enjoyment

After the weekend election in Australia, the Senate is going to be a strange mix of single interest parties along with the major parties. The whole issue seems to be with preferential voting, but as a result in the state of Victoria, a member of the Motoring Enthusiast Party has been elected. Apparently, a few things have been taken down of the web, some more embarrassing moments I'm guessing, but this comment caught my eye.

"We support a balanced approach towards sustainability of the environment and the use of the environment, both for the survival of mankind and for the unimpeded recreational use of the environment."

It is very clear from this that the environment is something for human use, for our survival and for our recreational use, by which he seems to mean four wheel driving, and is quoted again by the ABC as saying

"We have the RIGHT to express our individuality and freedom. Let's get a voice in the senate..... I am a Motoring Enthusiast and PROUD!"

Let's think about the worldview of Ricky Muir theologically.

Firstly, it's very clearly individualistic, as also evidenced by his view on taxation (again from the ABC)

"We are the only species on the planet who are forced to pay to exist," the post says.
"I think it is fair to say we should have the right to enjoy our existence with minimal government interference."

So governments interfere with our lives do they? Maybe so, but they fund schools, hospitals and other rights not shared in many places around the world and in many times in history. How else are the roads he no doubt loves paid for? Such hyper-individualism goes against the social contract of any society and is deeply anti-biblical. God loves the world, chooses a people, saves that people and the world with it. Too much Christianity echoes these sentiments, precisely because it has abandoned a biblical worldview. Taxation or not, governments play a role in maintaining order, something the bible affirms without accepting an unfettered mandate by human laws.

My other major observation is the incompatibility of unimpeded use and sustainability. The two words do not go together. Cars produce greenhouse gases which warm the plant unsustainably. Shifting to other energy sources and using cars less, not more, is important. The world is not our fun park. More than this, recreation doesn't have to be mechanical, it can involve many other activities that do not detract from the physical landscape or soundscape of 'wild' places. While I'm not advocating against 4WD use, having a political party where this is one of the few issues raised and where it is sought to be protected as a right shows how useless and watered down rights language has become.

It seems to me the bible promotes responsibility language far more, while providing the undergirding of rights for all humans as well as all non-humans and the earth itself. This isn't a deep green leveling of all life, but a biblical understanding that not everything is just about me, or my car.

Tuesday, September 3, 2013

Local stalling no end to global warming

A casual glance at plots of global mean temperature show something of a hiatus and yet many places are still showing warming. Russia had record heat wave in 2010, the USA in July 2012 and Australia continues to beat records. So what's up with that?

The climate undergoes internal variability in the form of various oscillations like the El Nino Southern Oscillation. During an El Nino, warm waters shift to the central or eastern Pacific and pressures drop there while waters cool in the western Pacific and pressures rise (for the more technically minded, westerly winds in the western Pacific produce waters in the ocean that transport warm water to the east and change the temperature structure of the ocean at and below the surface). During a La Nina, things are the other way around. Normal or neutral years represent a weak La Nina.

El Nino years are more warm globally. The shift of warm seas and lower pressures generates rainfall. As cloud forms, the atmosphere is heated and waves form, effecting weather patterns over north America. Heat is transferred away from the tropics more strongly in the northern hemisphere winter than during its summer. Hence, if the eastern Pacific is cooler than average (La Nina), northern hemisphere winters will be cooler because of the transport of that colder air. This transport of colder air can offset the warming produced by greenhouse gases.

When Kosaka and Xie (Nature, 2013,Published online) looked at global temperatures for 2002 to 2012, they saw that there was cooling during the northern hemisphere winter but warming during the northern hemisphere summer. To finish with a quote:

'All the climate models project a tropical Pacific warming in response to increased greenhouse gas concentrations [that's an increase in El Nino, MP]. We conclude that the recent cooling of the tropical Pacific and hence the current hiatus are probably due to natural internal variability rather than a forced response. If so, the hiatus is temporary, and global warming will return when the tropical Pacific swings back to a warm state. Similar hiatus events may occur in the future and are difficult to predict several years in advance owing to the limited predictability of tropical Pacific SST.'

So this is not good news or an overturning of ideas on climate change, merely the observation that the climate systems is always more complicated than we imagine. The 150+ year old science that burning fossil fuels increase the temperature, stands.

Pollution everywhere - keeping pure soundscapes

So I finally got and read Bernie Krause's book, The Great Animal Orchestra. I can highly recommend it. Krause looks at sound in the natural world, both biological and geological. He shows how over the years, changes in the health of the biosphere are visible (or more to the point audible) in the natural soundscape. Selective logging of forests reduces population of bird species. Aircraft sounds can silence the call of animals, making a hole in their aural herding and seeing them eaten.Whales are beached by very loud noises in the oceans, disorienting them. The natural world's soundscape is changed in so many ways.

The sounds of nature are the origins of music, and we seem keyed into some sounds that calm us. As I write I am listening to the sound of the waves, to ease the burden of an open office plan. As an introvert and someone sensitive to external sounds, I felt calmer yesterday and was more productive than when I used Coffivity and its human white noise.

Like pollution that spoils our water, warms our planet or drowns out the night sky with too much life, sound pollution drowns out the natural sounds we developed with. Many people are noise stressed by the sounds of modern life, noisy cars, industry, our digital devices and so on. As we insulate ourselves further from the world around us, it is hard to see how we can preserve it.

One of the fondest noises from my childhood is the warble of magpies and screech of galahs. The sounds of nature have a big place in my life. May there always be places of solitude to listen to the earth and her hymn of praise to the God who made and shapes her.