Tuesday, January 31, 2012

Earth's energy imbalance

Hansen et al. 2011

Hansen, J., Mki. Sato, P. Kharecha, and K. von Schuckmann, 2011: Earth's energy imbalance and implications. Atmos. Chem. Phys.,11, 13421-13449, doi:10.5194/acp-11-13421-2011.

Improving observations of ocean heat content show that Earth is absorbing more energy from the Sun than it is radiating to space as heat, even during the recent solar minimum. 

The inferred planetary energy imbalance, 0.58±0.15 W/m2 during the 6-yr period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. Observed surface temperature change and ocean heat gain together constrain the net climate forcing and ocean mixing rates. 

We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be -1.6±0.3 W/m2, implying substantial aerosol indirect climate forcing via cloud changes. 

Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. 

We conclude that recent slowdown of ocean heat uptake was caused by a delayed rebound effect from Mount Pinatubo aerosols and a deep prolonged solar minimum. Observed sea level rise during the Argo float era is readily accounted for by ice melt and ocean thermal expansion, but the ascendency of ice melt leads us to anticipate acceleration of the rate of sea level rise this decade.

Monday, January 30, 2012

World running out of resources: UN

Jill Colgan in Washington 
ABC News Online, January 31, 2012

A major United Nations report has called for a sustainable "evergreen revolution", warning that time is running out to ensure there is enough food, water and fuel to meet the needs of the world's rapidly growing population.
In a grim warning about the earth's increasing demand for resources, a panel led by the presidents of Finland and South Africa found demand will grow exponentially as the global population rises from 7 billion people to an expected 9 billion by 2040.
Within the next 20 years the world's population will need 50 per cent more food and vast new reserves of energy and water, according to UN estimates.
The report warns a failure to secure resources will condemn up to 3 billion people to poverty.
Billed as a blueprint for sustainability, the report urges governments to embrace green energy technologies and cut back on the use of non-renewable resources.
Its authors have urged governments to tackle sustainable development with a greater sense of urgency and political will.
"The current global development model is unsustainable. To achieve sustainability, a transformation of the global economy is required," the report said.
"Tinkering on the margins will not do the job. The current global economic crisis ... offers an opportunity for significant reforms."

Thursday, January 26, 2012

Flooding rated as worst climate change threat facing UK

Defra report lists 700 impacts, including flood risk for 3.6 million people, water shortages, soil erosion and wildlife disruption

Juliette Jowit,

The Guardian,   Thursday 26 January 2012

Flooding is the greatest threat to the UK posed by climate change, with up to 3.6 million people at risk by the middle of the century, according to a report published on Thursday by the environment department.

The first comprehensive climate change risk assessment for the UK identifies hundreds of ways rising global temperatures will have an impact if no action is taken. They include the financial damage caused by flooding, which would increase to £2bn-£10bn a year by 2080, more deaths in heatwaves, and large-scale water shortages by mid-century.

Unusually for such documents, it also highlighted ways in which the country could benefit from milder winters and drier summers, such as fewer cold-related deaths, better wheat crops and a more attractive climate for tourists.

"If you had to pick one particular issue I think the flooding issue is the most dominant," said Sir Bob Watson, chief scientist at the Department for Environment, Food and Rural Affairs.

Lord John Krebs, chairman of the adaptation committee of the independent advisory group Committee on Climate Change, said that without planning and investment to deal with the threats the UK would "sleepwalk into disaster". The benefits of climate change should also not be taken as reason to stop worrying about it, even with policies to reduce the threats, said Krebs: "Whether it will result in a net benefit we simply can't tell."

Scientists and other experts, led by Defra, identified 700 impacts of climate change in the UK, including the possibility of refugees arriving from wars over dwindling water and food.

High-impact events expected by mid-century included decreased forestation caused by red band needle blight, shortages in public water supply (especially in the north, Midlands and south of England), and worse water quality.

The assessors selected the 100 most pressing threats and opportunities and rated these according to their impact, the confidence of the modellers, and how soon the threats might occur. All the report's forecasts assume no governmental action to reduce or remove the threats.

The four most immediate "high consequence" risks all concerned flooding, with the expectation that in 10 years or so there will be increased flood damage to homes, with knock-on effects on insurance premiums and mental health.

Between 1.7 million and 3.6 million people are expected to be at risk of flooding by 2050, without investment to lessen the threat.

Surface water flooding would be likely to get worse, Watson added.

Other issues highlighted by the report include changes in wildlife migration, alterations in species communities as plants and animals fail to move fast enough to thrive, sewer overflows polluting the coast, changes in the soil, erosion from heavier rains, loss of staff working-time from heat stress, changes in fish stocks, and wildfires in drier summers.

The findings follow controversy over cuts to the UK flood defence budget.

However, Caroline Spelman, the environment secretary, said the report justified the department's decision to ask for more capital and fewer revenue funds from the Treasury, and said government money would be supplemented by contributions from local communities.

"[Comparing] the last four years of the Labour government and the first four years of this government there will be a reduction of 6% … but you can get more homes protected for the same amount of money," said Spelman.

The report was widely welcomed as a way to help government departments, businesses and councils plan ahead.

But Mary Creagh, the shadow environment secretary, said: "In 2010 Labour invested £354m in protecting homes from flooding, which has been cut by 27% to £259m a year for the next four years under this government.

"Ministers are playing Russian roulette with people's homes and businesses by cutting too far, too fast, and could leave communities blighted, with homeowners unable to insure, mortgage or sell their homes after 2013, when Labour's deal with the insurance industry runs out."

It will be seized upon by lobbyists to argue for spending priorities, and used by government to prepare the national adaptation plan, due to be published next year.

Julian Hunt, emeritus professor of climate modelling, at University College London, said the report's finding that there would be longer periods of "static weather" and cloud cover, could threaten energy from solar and wind sources .

"This leads to dangerous urban heat island temperatures and droughts. But it also indicates the danger of lengthy, very low, wind conditions, or cloudy conditions – so low-carbon energy alternatives to wind and solar are essential," said Hunt.

Peter Mallaburn, reader in climate policy at De Montfort University, said the need to save energy was in conflict with government policies not pushing for higher energy efficiency standards for commercial buildings.

"This report says, for the first time, that not only are our homes and offices leaky, but that they will start to overheat in a warmer world," said Mallaburn. "We need a coherent strategy to sort out this mess. Let's hope that this report acts as a wake-up call."

A website has been set up asking for the public's views on the national adaptation programme.

Tuesday, January 17, 2012

Climate warming would cause loss of life

 The Age, January 17, 2012 

A global temperature rise of two degrees by 2050 would result in increased loss of life, a new Australian study has found.

Scientists from the Queensland University of Technology and the CSIRO say they have conducted world-first research which looks at the "years of life lost" due to climate change.

They focused on the city of Brisbane, which has a subtropical climate.

"A two-degree increase in temperature in Brisbane between now and 2050 would result in an extra 381 years of life lost per year in Brisbane," lead 
researcher Associate Professor Adrian Barnett, from the university's Institute of Health and Biomedical Innovation, said in a statement.

"A two-degree increase in temperature is the figure in the United Nations Intergovernmental Panel on Climate Change says is dangerous, but could be reached unless more aggressive measures are undertaken to reduce greenhouse gas emissions."

Professor Barnett said an increase of more than two degrees would be catastrophic.

"A four-degree increase in temperature would result in an extra 3242 years of life lost per year in Brisbane."

Professor Barnett said the "years of life lost" measurement gives greater weight to deaths at younger ages instead of focusing just on elderly people.

"We wanted to use years of life lost because we suspected that many temperature-related deaths were in the elderly, which would reduce the public health importance of temperature compared with other issues," he said.

"In fact, we found the opposite, with a surprisingly high years of life lost figure."

Interestingly, the study found that a one-degree increase would result in a decrease in the number of lives lost.

This is believed to be because the increase in heat-related years of life lost are offset by the decrease in cold-related years of life lost. The researchers said cold-related deaths are significant, even in a city with Brisbane's warm climate.

And many deaths could be avoided if people have better insulation in their houses.

"Many houses in Brisbane are built of thin planks of wood and are poorly insulated, which means the occupants are exposed to whatever the temperature is outside," Professor Barnett said.

The researchers believe that while their work was focused on Brisbane, it contains helpful information to decision-makers in other areas as well.
The study has been published in the journal Nature Climate Change.

Thursday, January 12, 2012

Fourteen steps to reduce global warming

Nicky Phillips, SCIENCE 
The Age, January 13, 2012

REDUCING the amount of soot and methane released into the atmosphere could slow the world's warming by half a degree, save millions of lives, and dramatically improve global air quality, a study has found.

A group of international scientists claim 14 practical methods could reduce the pollutants, which not only contribute to global warming but also kill or debilitate millions of people each year, and increase global crop yields at the same time.

While much focus has been placed on reducing carbon dioxide emissions, methane – a powerful greenhouse gas – and black soot play a role in man-made global warming and are a significant source of air pollution.

By screening more than 400 tried-and-tested soot and methane pollution reduction processes being used on a small scale around the world, the team, led by NASA scientist Drew Shindell, came up with a list of approaches to improve air quality and reduce global warming that could be implemented on a regional and global scale.

Changes to coal mining and natural gas extraction combined with better landfill and livestock management would reduce global methane, while improvements to diesel engines, replacing wood and dung fires with modern stoves and banning agricultural burning would lower soot emissions.

To measure the impact these pollution reduction methods could have on global warming, the team added the controls to computer models using two future emissions scenarios – one based on business as usual, where carbon emissions were not constrained, and one based on a low-carbon world.

The results show global temperature could be decreased by half a degree by 2050.

And, in a low-carbon world, the soot and methane reductions would keep the world's thermostat below the danger level of 2 degrees warming.

Lower methane levels would avoid annual crop losses of between 30 million and 137 million tonnes in 2030, while soot reductions would prevent between 700,000 and 4.7 million premature deaths a year.

The cost benefits to reducing the pollutants were also significant, said the scientists, who published their findings in the journal Science.

"Methane emission reductions are valued at $700 to $5000 per metric tonne, which is well above the typical marginal abatement costs, [of about] $250," they said.
An atmospheric chemist at the CSIRO said that, scientifically, the research was "a very strong piece of work".

Melita Keywood, a principal research scientist at CSIRO Marine and Atmospheric Research, said: "The measures are the sort of things that can be done now, and can have a short-term consequence which will really appeal to policymakers."

Monday, January 9, 2012


Hot Topic by GUEST on JANUARY 10, 2012

Climate change is happening now and Australia is in the firing line says Jim Salinger in this guest post. This article first appeared in the Dominion Post.

As I watch from my summer subtropical perch in Brisbane, Queensland, the somewhat unprecedented rains that deluged parts of Australia during the summer of 2010/11 have been replaced by sizzling heat waves this summer. These raise some pertinent lessons on climate and risk management for New Zealand. Firstly let's look at some figures and ask the question of what are the climate mechanisms behind the heat waves.

For December 2011 the Bureau of Meteorology figures show that the highest temperatures of the year occurred in the third Australian heat wave of the year. This affected the Pilbara region in the north west of Western Australia. Multiple sites broke the previous Western Australian December record of 48.8ºC on December 26, 1986 with Roebourne recording 49.4ºC on December 21, Onslow Airport recording 49.2ºC on the 22nd and Learmonth 48.9ºC on the 23rd. Roebourne's 49.4ºC was the highest temperature recorded in Australia since 1998.

This month incessant heat has struck the interior with daytime highs soaring to the mid forties. As I pen this there are a few more days of this heat wave left with temperatures averaging between 35ºC and 40ºC in central Australia. Places have been recording daily lows of 30ºC and daily highs of close to 45ºC. Mean temperatures have been running over 6ºC above average.

Meteorologists measure the warmth of the air lying above one spot as the 500 – 1000 hPa thickness. The "thickness" is a measure of how warm or cold a layer of the atmosphere is. High values mean warm air, and low values mean cold air. Summer 500 – 1000 hPa thickness values lie between 5600 and 5700 metres over Australia. It was values of around 5760 metres that brought New Zealand's highest temperatures in the low forties in February 1973.

And what has been happening in late December and early January? An incredibly hot blob of air has sat over parts of inland Australia with thickness values of 5850 metres or more.

It is a simple law of physics that with more greenhouse gases in a layer of atmosphere the warmer surface temperatures get. Atmospheric concentrations of carbon dioxide now are at 392 parts per million compared with 280ppm in 1750. This means that the lower atmosphere is thicker and retains more warmth, as more carbon dioxide in the atmosphere traps extra heat. The consequence is that global warming leads to an increase in the magnitude and incidence of heat waves.

The first lesson from the sizzling continental heat wave is that global warming has arrived for some time now, and the climate has warmed. Global warming is no longer a theory based on abstract calculations of what the climate is very likely to do in future decades. In 2007 the Intergovernmental Panel on Climate Change (IPCC) concluded: "It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent."

The second lesson – the canary in the coal mine – is that because of global warming the frequency of these extreme weather events is only going to increase. Thus the century old high temperature extremes are going to be exceeded more often in the future.

The third lesson is that there needs to be better preparation for these events by civil society. Heat waves can have debilitating effects on the elderly who are not so healthy. The 2003 European heat wave caused at least 40,000 deaths and the 2010 western Russian heat wave 55,000 deaths. Heat waves also increase the fire risk when there is little rain, as occurred in the Black Saturday heat wave and bushfires on 7 February 2009 in Victoria.

At least New Zealand is the lucky country in this respect surrounded by oceans which dampen down any high temperatures. However NIWA future climate scenarios show a large increase in days above 30 and 35ºC in eastern districts with more frequent very hot nor'westers as the 21st century progresses.

Global warming is here, now and not a phenomenon for future generations to deal with. We must embark on a course of emissions reductions targets as soon as possible, to claw back rapidly rising greenhouse gas levels in the atmosphere. If we do not act now the severity of such heat waves and the subsequent damage to life and property will increase. There is no time like the present to invest in our future wellbeing.

Jim Salinger is spending the southern summer at the National Climate Change Adaptation Research Facility at Griffiths University, Queensland as a visiting research fellow.