In the link above, Graham Readfearn goes into some detail on the likely melting prospects of East Antarctica in particular. The salient points are as follows:
- Currently ice sheets only account for one sixth of 3.2mm of sea level rise each year. However this could change dramatically.
- During the Pliocene, about 3 million years ago, atmospheric CO2 levels were similar to today’s and the temperature reached 2 to 3°C above pre-industrial. The sea level was some 20 metres higher than today.
- Using models, the contribution from East Antarctica was calculated at about 14 metres from East Antarctica, and 3 metres from West Antarctica.
To me that doesn’t leave enough space for Greenland, other land ice, and thermal expansion. Nevertheless, East Antarctica is likely to be significantly implicated.
The bottom line, I think, is that somewhere beyond 1°C of warming the ice sheets are likely to go critical. The increase in melting could then be more geometric than linear and we could be committed to unstoppable melting for thousands of years. The time to act is now.
2. Sea level rising faster than previously thought
New research by Christopher Watson and others compared tidal gauge records with satellite records since 1993, and found that the satellite slightly overestimated sea level rise for the first six years of that period. They estimate that it should have been 2.6 to 2.9mm. The current rate is 3.2mm.
The bottom line is that sea level rise is increasing, rather than slightly decreasing, which had puzzled scientists.
The current rate is double the 20th century average.
The Larsen A ice shelf collapsed in 1995, Larsen B went in 2002. The latter was 3,250 square kilometres and it’s collapse was without precedent since the last ice age.
Larsen C is 55,000 square kilometres, about half the size of Iceland and the fourth largest in the world. It is now known to be melting from above and below, and apparently a crack is developing.
It acts as a giant plug, holding back an array of glaciers. Probably it will hang on for a time, but no-one can be sure when it will go. When it does the effect could be a spurt in global sea level rise from the glaciers the ice sheet is holding back. For reasons like this, sea level rise is not a linear process when considered over decades and centuries.
See also at The Carbon Brief.
Separately, there is a 625 square mile Larsen B remnant, half the size of Rhode Island, due to crash any time soon.
4. 19 reasons why the world is missing the 2°C climate change limit
The IEA maps three scenarios: 6°C, or business as usual; 4°C, where we are heading with existing mitigation commitments; and a 50/50 chance of avoiding 2°C.
It looks at progress in 19 categories, which Carbon Brief have condensed into one graphic:
- Five areas, carbon capture and storage (CCS), coal, nuclear, building energy use and building energy efficiency are all off track, the IEA says (red squares, below).
The remaining 14 areas including renewables, industry, transport, electric vehicles, energy storage and hydrogen have seen improvements, but need to progress faster if they are to hit their climate milestones (orange squares).
The gloomy outlook is moderated for some areas, such as CCS, where recent developments have been more positive (green arrows). For instance, renewable power production will increase by half between 2013 and 2020, the IEA says, with some green sources now competitive with new fossil generation in come countries.
No green squares – trouble everywhere!
- The new Labor government in Queensland has confirmed its commitment to generating 50 per cent of its electricity needs from renewable energy by 2030…
And it is establishing a state-based Productivity Commission to plot a policy pathway to get there.
[Energy minister Mark] Bailey said the government also wanted to lift the number of households with rooftop solar from its current levels of more than 400,000 to one million by 2020.
6. El Niño declared
We are headed for an El Niño and it could be a big one. This is what the rainfall effects of 12 moderate to strong El Niños look like:
The coastal strip which includes Brisbane looks like decile 4. It’s just that every time they predict decile 4 we seem to get decile 1.
Some 80% of Queensland is already drought declared.
An El Niño increases the chances that 2015 could be the warmest year ever.