Is the fish on your plate older than your grandmother?

The Conversation: The real cost of taking fish out of the water. This excellent piece gives a good snapshot of overfishing (the carbon footprint of fishing was something I didn't realise until reading this). It also suggests one of the ways we can be part of the solution: by eating less fish, and eating smarter, which means either checking sites like Good Fish Bad Fish (an Australian version; UK readers can use the Good Fish Guide) or asking questions of potential fish meals such as: "Are they older than your grandmother? Did catching them kill tonnes of other innocent species? How much carbon was used to get it onto your plate?"

Al Jazeera: Overpopulation is not to blame for famine. The causes are famine in the Horn of Africa are complex. Simplistic analyses that blame a single factor do not help.

Guardian: Salty rice is not so nice - rising seas, rising salt in the Mekong. Concerns about sea level rise are not limited to infrastructure damage or coastal erosion; salination is the big issue in many places and especially for the densely-populated Mekong delta.

Grist: The great oyster crash. This is where ocean acidification is starting to bite.

CP: S&P Downgrades Planet Earth and Humanity. This will only make sense if you have been following recent US economic news.

Larry Elliott: The global economy is not in good shape. The crisis from 2008 has not gone away; it has simply shifted form.

Mongabay: Conflict correlates with warm weather, at least in the tropics. This isn't good news in a warming world.

Guardian: One billion cars. "Between 2000 and 2010, the number of cars and motorcycles in China increased twentyfold. In the next 20 years it is forecast to more than double again, which means there will be more cars in China in 2030 than there were in the entire world in 2000."

A world without beaches?

Having been reading various papers and reports on climate change for some time now, I thought I had a pretty good grasp on the range of negative effects associated with the unprecedented rate of change our actions are causing in the planet's atmosphere and oceans: higher temperatures, changing patterns of precipitation, more frequent heat waves and bushfires, more intense storms and floods, habitat destruction, biodiversity decline, cryosphere melt, reduced agricultural yields, increased water stress, increased area affected by drought at any one time, ocean acidification (which is not directly related to climate, but has the same cause: rising carbon dioxide levels), modified vector borne disease spread (such as dengue and malaria), exacerbation of respiratory health issues associated with ground-level ozone (smog), human migration patterns (refugees), desertification, shifting ocean currents, warming oceans, coral bleaching and mortality, poleward movement of the tropics, destabilisation of permafrost, shifts in the timing of annual events such as flowering, hibernations, migrations and peak river flows, sea level rise and the consequent threat to infrastructure during storm surges as well as salination of coastal water tables. All these I've read a fair bit about over the last couple of years. But only recently I have come across an implication that I hadn't heard before, one with a high visual and emotional impact for many people, but which, as far as I can tell, is not yet widely known.

Much has been said about sea level rise, and I don't intend to give a full account here. But quite apart from the risk of flooding, rising seas mean coastal erosion. I had not grasped how significant this could be. A rule of thumb used by some researchers is that, roughly speaking, for each centimetre of sea level rise, coasts will erode by one metre. When we are looking at a likely sea level rise between 50 and 200 centimetres by 2100 (and continuing thereafter for some time), you quickly get a sense of the scale of this particular issue. Sea defences can be built to minimise this impact, but they are only partially or temporarily effective (or extremely expensive), especially against the scale of change we are looking at.

Where the public at large are likely to particularly notice this, especially in Australia, is in its effect on beaches, many of which are likely to be progressively stripped of sand over the coming decades. The processes involved are complex and only partially understood, and there may be much local variation in how sea level rise affects coastal areas. Nonetheless, loss of sand is already a major (and costly) headache for many beaches and the best estimates are that this will generally get worse.

Many of us are likely to live to see a world virtually free of summer Arctic sea ice; our children may see the last of the great coral reefs die; our grandchildren may need an explanation of what a sandy beach was.

Calvin the Greenie

"The earth was given to man, with this condition, that he should occupy himself in its cultivation... The custody of the garden was given in charge to Adam, to show that we possess the things which God has committed to our hands, on the condition that, being content with the frugal and moderate use of them, we should take care of what shall remain. Let him who possesses a field, so partake of its yearly fruits, that he may not suffer the ground to be injured by his negligence, but let him endeavor to hand it down to posterity as he received it, or even better cultivated. Let him so feed on its fruits, that he neither dissipates it by luxury, nor permits it to be marred or ruined by neglect. Moreover, that this economy, and this diligence, with respect to those good things which God has given us to enjoy, may flourish among us; let everyone regard himself as the steward of God in all things which he possesses. Then he will neither conduct himself dissolutely, nor corrupt by abuse those things which God requires to be preserved."

- John Calvin on Genesis 2.15 in Commentary on Genesis (1554).

The earth was given to us. And, at the same time, we were given to the earth, to till it and keep it.

A recent study found that one quarter of the earth's arable land has been degraded through soil erosion, salinisation, desertification or nutrient exhaustion.