Climate change : already happening too fast…!

Snow leopard

So it begins…. A study has shown that the speed of evolutionary change is far outstripped by the rate of global warming, meaning many creatures will face extinction. Robin McKie of The Observer reports

PS: The UK wanted to take climate change topic ‘out’ of the curriculum – but have now dropped these plans! NAEEUK says ‘just as well’ 

Among the many strange mantras repeated by climate change deniers is the claim that even in an overheated, climate-altered planet, animals and plants will still survive by adapting to global warming. Corals, trees, birds, mammals and butterflies are already changing to the routine reality of global warming, it is argued.

Certainly, countless species have adapted to past climate fluctuations. However, their rate of change turns out to be painfully slow, according to a study by Professor John Wiens of the University of Arizona. Using data from 540 living species, including amphibians, reptiles, birds and mammals, Wiens and colleagues compared their rates of evolution with the rates of climate change projected for the end of this century. The results, published online in the journal Ecology Letters, show that most land animals will not be able to evolve quickly enough to adapt to the dramatically warmer climate expected by 2100. Many species face extinction, as a result.

“We found that, on average, species usually adapt to different climatic conditions at a rate of only by about 1C per million years,” Wiens explained. “But if global temperatures are going to rise by about four degrees over the next 100 years as predicted by the Intergovernmental Panel on Climate Change, that is where you get a huge difference in rates. What that suggests overall is that simply evolving to match these conditions may not be an option for many species.”

The study indicates there is simply not enough time for species to change their morphologies – for example, by altering their bodies’ shapes so they hold less heat – to compensate for rising heat levels. Too many generations of evolutionary change are required. Nor is moving habitat an option for many creatures. “Consider a species living on the top of a mountain,” says Wiens. “If it gets too warm or dry up there, they can’t go anywhere.”

The crucial point of the study is that it stresses a fact that is often conveniently ignored by climate change deniers. It is not just the dramatic nature of the changes that lie ahead – melting icecaps, rising sea levels and soaring temperatures – but the extraordinary speed at which they are occurring. Past transformations that saw planetary temperatures soar took millions of years to occur. The one we are creating will take only a few generations to take place. Either evolution speeds up 10,000-fold, which is an unlikely occurrence, or there will be widespread extinctions.

CLIMATE CHANGE : Global carbon dioxide in atmosphere passes milestone level

Mean surface temperature change for 1999–2008 ...

Mean surface temperature change for 1999–2008 relative to the average temperatures from 1940 to 1980 (Photo credit: Wikipedia)


For the first time in human history, the concentration of climate-warming carbon dioxide in the atmosphere has passed the milestone level of 400 parts per million (ppm). The Guardian reports

The last time so much greenhouse gas was in the air was several million years ago, when the Arctic was ice-free, savannah spread across the Sahara desert and sea level was up to 40 metres higher than today.

These conditions are expected to return in time, with devastating consequences for civilisation, unless emissions of CO2 from the burning of coal, gas and oil are rapidly curtailed. But despite increasingly severe warnings from scientists and a major economic recession, global emissions have continued to soar unchecked.

“It is symbolic, a point to pause and think about where we have been and where we are going,” said Professor Ralph Keeling, who oversees the measurements on a Hawaian volcano, which were begun by his father in 1958. “It’s like turning 50: it’s a wake up to what has been building up in front of us all along.”

“The passing of this milestone is a significant reminder of the rapid rate at which – and the extent to which – we have increased the concentration of greenhouse gases in the atmosphere,” said Prof Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change, which serves as science adviser to the world’s governments. “At the beginning of industrialisation the concentration of CO2 was just 280ppm. We must hope that the world crossing this milestone will bring about awareness of the scientific reality of climate change and how human society should deal with the challenge.”

The world’s governments have agreed to keep the rise in global average temperature, which have already risen by over 1C, to 2C, the level beyond which catastrophic warming is thought to become unstoppable. But the International Energy Agency warned in 2012 that on current emissions trends the world will see 6C of warming, a level scientists warn would lead to chaos. With no slowing of emissions seen to date, there is already mounting pressure on the UN summit in Paris in 2015, which is the deadline set to settle a binding international treaty to curb emissions.

Edward Davey, the UK’s energy and climate change secretary, said: “This isn’t just a symbolic milestone, it’s yet another piece of clear scientific evidence of the effect human activity is having on our planet. I’ve made clear I will not let up on efforts to secure the legally binding deal the world needs by 2015 to avoid the worst effects of climate change.”

Two CO2 monitoring stations high on the Hawaiian volcano of Mauna Loa are run by the US National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography and provide the global benchmark measurement. Data released on Friday shows the daily average has passed 400ppm for the first time in its half century of recording. The level peaks in May each year as the CO2 released by decaying vegetation is taken up by renewed plant growth in the northern hemisphere, where the bulk of plants grow.

Analysis of fossil air trapped in ancient ice and other data indicate that this level has not been seen on Earth for 3-5 million years, a period called the Pliocene. At that time, global average temperatures were 3 or 4C higher than today’s and 8C warmer at the poles. Reef corals suffered a major extinction while forests grew up to the northern edge of the Arctic Ocean, a region which is today bare tundra.

“I think it is likely that all these ecosystem changes could recur,” said Richard Norris, a colleague of Keeling’s at Scripps. The Earth’s climate system takes time to adjust to the increased heat being trapped by high greenhouse levels and it may take hundreds of years for the great ice caps in Antarctica and Greenland to melt to the small size of the Pliocence and sea level far above many of the world’s major cities.

But the extreme speed at which CO2 in now rising – perhaps 75 times faster than in pre-industrial time – has never been seen in geological records and some effects of climate change are already being seen, withextreme heatwaves and flooding now more likely. Recent wet and cold summer weather in Europe has been linked to changes in the high level jetstream winds, in turn linked to the rapidly melting sea ice in the Arctic, which shrank to its lowest recorded level in September.

“We are creating a prehistoric climate in which human societies will face huge and potentially catastrophic risks,” said Bob Ward, policy director at the Grantham Research Institute on Climate Change at the London School of Economics. “Only by urgently reducing global emissions will we be able to avoid the full consequences of turning back the climate clock by 3 million years.”

“The 400ppm threshold is a sobering milestone and should serve as a wake up call for all of us to support clean energy technology and reduce emissions of greenhouse gases, before it’s too late for our children and grandchildren,” said Tim Lueker, a carbon cycle scientist at Scripps.

Professor Bob Watson, former IPCC chair and UK government chief scientific adviser, said: “Passing 400ppm of carbon dioxide in the atmosphere is indeed a landmark and the rate of increase is faster than ever and shows no sign of abating due to a lack of political committment to address the urgent issue of climate change – the world is now most likely committed to an increase in surface temperature of 3C-5C compared to pre-industrial times.”

The graph of the rising CO2 at Mauna Loa is known as the Keeling curve, after the late Dave Keeling, the scientist who began the measurements in March 1958. The isolated Hawaiian island is a good location for measurements as it is far from the main sources of CO2, meaning it represents a good global average.

Global warming is not due to the sun, confirms leaked IPCC report

Key Note presentation by Vicente Barros , Co-c...

Key Note presentation by Vicente Barros , Co-chair of Working Group II, Intergovernmental Panel on Climate Change (IPCC) (Photo credit: Citt)

Climate sceptics’ claims that UN climate science panel’s AR5 report show the sun is causing global warming don’t stack up. The Guardian reports

La Niña Conditions. Warm water is farther west...

La Niña Conditions. Warm water is farther west than usual. (Photo credit: Wikipedia)

Alec Rawls, an occasional guest poster on the climate contrarian blog WattsUpWithThat who signed up to review the upcoming Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (as anyone can), has “leaked” a draft version of the report and declared that it “contains game-changing admission of enhanced solar forcing.”  This assertion was then repeated by James Delingpole atThe Telegraph (with some added colorful language), and probably on many other climate contrarian blogs.

If the IPCC were to report that the sun is a significant player in the current rapid global warming, that would indeed be major news, becausethe body of peer-reviewed scientific literature and data clearly show that the sun has made little if any contribution to the observed global warming over the past 50+ years (Figure 1).

contributors 50

Figure 1: Percent contributions of greenhouse gases (GHGs), sulfur dioxide (SO2), the sun, volcanoes, and El Niño Southern Oscillation (ENSO) to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004(M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple)Huber and Knutti 2011 (HK11, light blue), Gillett et al. 2012(G12, orange), and Wigley and Santer 2012 (WS12, dark green).

So why would the latest IPCC report contradict these studies when its purpose is to summarize the latest and greatest scientific research?  The answer is simple — it doesn’t.  Rawls has completely misrepresented the IPCC report.

The supposedly “game-changing admission” from the IPCC report is this:

“Many empirical relationships have been reported between GCR [galactic cosmic rays] or cosmogenic isotope archives and some aspects of the climate system…The forcing from changes in total solar irradiance alone does not seem to account for these observations, implying the existence of an amplifying mechanism such as the hypothesized GCR-cloud link.”

This statement refers to a hypothesis of Henrik Svensmark from theDanish National Space Institute, who has proposed that galactic cosmic rays (GCRs) could exert significant influence over global temperatures. The GCR hypothesis suggests that when they reach Earth, GCRs (high-energy charged particles originating from somewhere in our galaxy) are capable of “seeding” clouds; thus at times when a lot of GCRs are reaching the Earth’s surface, more clouds will form.  Clouds generally have a cooling effect on the Earth’s temperature, because they reflect sunlight.

So the hypothesis goes like this: high solar activity means a strong solar magnetic field, which deflects more GCRs away from Earth, which means less cloud formation, which means less sunlight is reflected away from Earth, which means more warming.  This GCR-caused warming would amplify the warming already being caused by increased solar activity.  Conversely, cooling from decreased solar activity would hypothetically be amplified by more GCRs on Earth, more clouds, more reflected sunlight, and thus more cooling.

It’s important to note that so far virtually all scientific research on GCRshas shown that they are not effective at seeding clouds and thus have very little influence over the Earth’s temperature.  In fact, as Zeke Hausfather has noted, the leaked IPCC report specifically states this:

“…there is medium evidence and high agreement that the cosmic ray-ionization mechanism is too weak to influence global concentrations of [cloud condensation nuclei] or their change over the last century or during a solar cycle in any climatically significant way.”

But more importantly in this context, even if GCRs did influence global temperature, they would currently be having a cooling effect.

Rawls also provides the following quote from the IPCC report (emphasis added):

“There is very high confidence that natural forcing is a small fraction of the anthropogenic forcing. In particular, over the past three decades (since 1980), robust evidence from satellite observations of the TSI [total solar irradiance] and volcanic aerosols demonstrate a near-zero (–0.04 W m–2) change in the natural forcing compared to the anthropogenic AF increase of ~1.0 ± 0.3 W m–2.”

The term “radiative forcing” refers to a global energy imbalance on Earth, which may be caused by various effects like changes in the greenhouse effect or solar activity.  A positive forcing will result in warming temperatures, while a negative forcing will result in cooling.

Here the IPCC is saying that since 1980, the sun and volcanoes have combined to cause a slightly negative global energy imbalance, which means they have had a slight cooling influence on global temperatures over the past three decades.  Indeed, solar activity has decreased a bit over that timeframe (Figure 2).

Figure 2: Global temperature (red, NASA GISS) and Total solar irradiance (blue, 1880 to 1978 from Solanki, 1979 to 2009 from PMOD), with 11-year running averages.

As we would expect, lower solar activity including a weaker solar magnetic field has translated into a slight increase in GCR flux on Earth (Figure 3).  Note that on the left-hand axis of Figure 3, GCR countsdecrease going up the axis in order to show the relationship with temperature, since fewer GCRs hypothetically means fewer clouds, less reflected sunlight, and higher temperatures.

cosmic rays vs temps

Figure 3: Global average surface temperature (red, NASA GISS) vs. GCR flux on Earth (blue, Krivova & Solanki 2003), with 11-year running averages.

So, if GCRs really do amplify the solar influence on global temperatures, since 1980 they are amplifying a cooling effect.  In fact, GCRs reaching Earth recently hit record high levels (Figure 4), yettemperatures are still way up.

Figure 4: Record cosmic ray flux observed in 2009 by the Advanced Composition Explorer (NASA)

Rawls has argued to the contrary by claiming that the climate is still responding to the increase in solar activity from the early 20th century, and that GCRs are amplifying that solar warming from over 60 years ago.  This argument is simply physically wrong.  As Figure 2 illustrates, when solar activity rises, temperatures follow suit very soon thereafter.  In fact, during the mid-20th century, solar activity and global surface temperatures both flattened out.  Are we to believe that the planet suddenly began responding to the pre-1950 solar activity increase in 1975—2012, after not warming 1940—1975?  The argument makes no physical sense.

On top of that, the hypothetical GCR process is a relatively rapid one.  Cloud formation from GCR seeding should occur within days, and clouds have very short lifetimes.  For GCRs to have a warming effect, solar activity must be increasing right now.  It is not, in fact solar activity has been essentially flat and slightly declining in recent decades.  Changes in solar activity from 60+ years ago have no bearing whatsoever on GCRs today.

To sum up,


  • The leaked IPCC report states that there may be some connection between GCRs and some aspects of the climate system.


  • However, the report is also consistent with the body of scientific literature in stating that research indicates GCRs are not effective at seeding clouds and have very little influence on global temperatures.


  • Solar activity has been nearly flat and slightly decreasing in recent decades, meaning that if GCRs do amplify solar influences on climate, they are amplifying a cooling effect.


The body of peer-reviewed scientific literature is very clear: human greenhouse gas emissionsnot solar activity or galactic cosmic rays, are causing global warming.  The leaked IPCC report is entirely consistent with this conclusion.  In fact, in attempting to argue to the contrary, Rawls has scored an own goal by showing that if anything, GCRs are currently amplifying a solar cooling effect.

Sea-level rise from polar ice melt finally quantified

Subglacial topography and bathymetry of bedroc...

Subglacial topography and bathymetry of bedrock underlying Antarctica ice sheet (Photo credit: Wikipedia)

Melting of polar ice sheets has added 11mm to global sea levels over the past two decades, according to the most definitive assessment so far. From BBC News website 

A helicopter is taking off Greenland Ice Sheet

A helicopter is taking off Greenland Ice Sheet (Photo credit: Wikipedia)

More than 20 polar research teams have combined forces to produce estimates of the state of the ice in Greenland and Antarctica in a paper in Science.

Until now different measurement means have produced a wide range of estimates with large uncertainties.

But sea-level rise is now among the most pressing questions of our time.

Polar ice has a tremendous capacity to cause massive rises – with huge potential impacts on coastal cities and communities around the world.

But the remoteness and sheer size of the ice sheets mean accurate measurements are a serious challenge even for satellites which have to distinguish snow from ice, and the rise of the land from the shrinking of the ice.

One number

The new estimate shows that polar melting contributed about one-fifth of the overall global sea level rise since 1992; other factors include warming that causes the seawater to expand.

The study does not seek to forecast future change.

Supported by US and European space agencies Nasa and Esa, the research brought together data from satellites measuring the surface altitude, the flow of the glaciers and the gravitational effect of the ice mass to produce the first joint assessment of how the ice sheets are changing.

Prof Andrew Shepherd explains the findings to David Shukman

The results show that the largest ice sheet – that of East Antarctica – has gained mass over the study period of 1992-2011 as increased snowfall added to its volume.

However, Greenland, West Antarctica and the Antarctic Peninsula were all found to be losing mass – and on a scale that more than compensates for East Antarctica’s gain.

The study’s headline conclusion is that the polar ice sheets have overall contributed 11.1mm to sea level rise but with a “give or take” uncertainty of 3.8mm – meaning the contribution could be as little as 7.3mm or as much as 14.9mm.

Continue reading the main story

“Start Quote

The next big challenge… is to predict what will happen over the next century”

Hamish PritchardBritish Antarctic Survey

The combined rate of melting from all the ice sheets has increased over the past 20 years with Greenland losing five times as much now as in 1992.

The lead author of the research, Prof Andrew Shepherd of Leeds University, said the study brought to an end 20 years of disagreement between different teams.

“We can now say for sure that Antarctica is losing ice and we can see how the rate of loss from Greenland is going up over the same period as well,” he added.

“Prior to now there’d been 30 to 40 different estimates of how the ice sheets are changing, and what we realised was that most people just wanted one number to tell them what the real change was.

“So we’ve brought everybody together to produce a single estimate and it turns out that estimate is two to three times more reliable than the last one.”


Prof Shepherd said the measurements were in line with climate change predictions.

“We would expect Greenland to melt more rapidly because the temperatures have risen,” he said.”We would expect West Antarctica to flow more quickly because the ocean is warmer. And we would also expect East Antarctica to grow because there’s more snowfall as a consequence of climate warming.”

Dr Erik Ivins, a co-author from Nasa’s Jet Propulsion Laboratory, said one issue that had “plagued” ice-sheet studies was land springing up in a process called “post-glacial rebound” – with effects as high as 1cm per year.

But the use of GPS to measure vertical motion and estimates of the ice sheets’ movements over the past 21,000 years had allowed the rebound effect to be properly understood.

“The new estimates from space gravity for Antarctica’s ice sheet loss rates are lowered by using these improved post-glacial rebound models,” Dr Ivins said.

“The results, then, are more consistent with other space observations that were taken over the past decade. This is one of the major findings in the inter-comparison effort by this international team of scientists.”

The findings are in line with the broad range of forecasts in the 2007 assessment by the UN’s Intergovernmental Panel on Climate Change.

And they were completed in time to be considered for the next report, due in September next year.

Another author, Dr Hamish Pritchard of the British Antarctic Survey, said: “The next big challenge – now that we’ve got quite a good understanding of what’s happened over the last 20 years – is to predict what will happen over the next century.

“And that is going to be a tough challenge with difficult processes going on in inside the glaciers and ice sheets.”

Spiegel: ‘The Truth Peddlers’ – Smoke and Mirrors in the Climate Debate

Reduction of flood and associated extreme weat...

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From | Follow the discussions also on my  twitter .

A new book by an executive at a major German power ultility claims we aren’t facing a climate catastrophe and rejects current mainstream ideas on global warming. Both climate change skeptics and those who warn of global warming profit from such controversies — so who should we believe?

Science can be so easy — at least when it is stripped of its nuances. Fritz Vahrenholt and his colleague, geologist Sebastian Lüning, say the world isn’t facing a climate catastrophe. The two are peddling precisely the kind of theory that generates publicity and allows both sides of the debate to profit. But it also leaves people wondering who they should believe.

The authors both work for German electric utility company RWE, where Vahrenholt is an executive. In their book “Die Kalte Sonne” (“The Cold Sun”), they claim that important research about climate change has been kept under wraps and that cries of an impending climate catastrophe are misleading. Their book arrived in book stores in Germany last week, with considerable media attention.

Following their statements, newspapers like the conservative tabloid Bild are dismissing what they call the “CO2 lie.” This camp says it’s not greenhouse gases that are behind the problem. It’s the sun that determines climate change, they argue.

The book is the latest salvo in the ongoing debate over global climate change. It’s a perpetual conflict that leaves people asking questions like: What’s really going on with the climate? What kind of picture can you draw from current research? The most reliable source on the topic is the climate report produced by the United Nations. The Intergovernmental Panel for Climate Change (IPCC) puts together a report every few years about the state of knowledge in the field. The report documents in detail where researchers are unsure or just don’t know. Contrary to what many IPCC critics say, however, the report reads like a book filled with doubts. But there’s also a “summary for political decision makers” section, which is put together by civil servants rather than researchers, and which can appear to be biased in places.

Source :

Wildlife Update : Why protecting the world’s nature is good for our wallets

The Economics of Ecosystems and Biodiversity

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A new world body on wildlife and ecosystems protection being set up by the UN must avoid blaming developing nations, where most of the world’s biodiversity loss is occurring, says a top British scientist.


Overconsumption by rich western nations is as big a driver of global environmental degradation as the rapidly growing populations of developing countries, says Professor Bob Watson, a leading figure in setting up the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES).

The new body – modelled on the UN’s Intergovernmental Panel on Climate Change (IPCC) – will assess how and why the natural world is being degraded, what it will cost society, and what can be done to halt the process.

But it must avoid rows between rich and poor countries, says Professor Watson, an ex-head of the IPCC, who is Chief Scientific Adviser to Britain’s Department for Environment, Food and Rural Affairs. “If they think this is just the white world, the developed world, telling them what to do, that’ll be the end of it … The climate debate has been, ‘you rich countries got rich by using cheap fossil fuels, and now you’re telling us not to use them.’ We must not get into that,” he said. Regional assessments of biodiversity problems must be “owned” by the regions concerned, he said. So if there is a regional biodiversity assessment of Latin America, scientists from Latin America will carry it out, not foreign scientists.

Professor Watson will play a key role at a Nairobi meeting today which will decide how the new body can be formed, probably next year. Hopes are high that the IPBES might help halt the loss of global wildlife and habitats.

The IPBES is based on the increasingly influential concept of ecosystem services, that forests rivers or peat bogs are not just parts of the natural world, but produce oxygen, provide food and store atmospheric carbon, vital in the fight against climate change.

The new body, which all the major global nations back, follows on the heels of two reports: the Millennium Ecosystems Assessment of 2005, which showed that most of the world’s ecosystems are in serious decline, and the report on The Economics of Ecosystems and Biodiversity released last year, which estimated that nature and the services it provides are worth trillions of dollars annually to society.

The IPBES will aim to show the value of biodiversity both in ethical or social terms, and in economic terms.

Professor Watson is seen as the ideal person to oversee the UN’s biodiversity body, as he has led international environmental assessments of all major global concerns: ozone depletion, climate change, ecosystem change and agriculture and development.

In fact, the 63-year-old atmospheric chemist, from Romford, east London, who still speaks with an East End accent, is the world’s leading authority on policy responses to global change. Yet he is far from being a household name in Britain since he spent 34 years of his career in the US, where he held senior positions in NASA, the Clinton White House, and the World Bank. He chaired the IPCC from 1997 to 2002.

He says global ecosystems face a “headlong assault” from five drivers – land conversion (such as deforestation), over-exploitation (such as overfishing), the introduction of exotic species, pollution, and climate change.

And he does not think climate change can be stopped at a rise of two degrees Celsius, which is the goal of most world climate policy. “We had better be prepared to adapt to four degrees,” the professor commented.

What the ecosystem is worth

Ask yourself what human society gets from a forest and the obvious answer is wood. Another obvious answer might be wildlife. Or perhaps, a pleasurable stroll. But that doesn’t begin to list the benefits provided to us by a great aggregation of trees.

Forests such as the Amazon are ecosystems which provide the world with tremendous services that are essential to the continuance of human life. These include vast amounts of oxygen, and fresh water, and a beneficial climate, as well as the storing of billions of tonnes of the carbon dioxide which human industry is pumping into the atmosphere and which is causing the world to heat up, with potentially disastrous consequences. And at last, the real value of these ecosystem services is being realised.

Last year the UN released a ground-breaking report on The Economics of Ecosystems and Biodiversity which put monetary value on the benefits the natural world provides us with. It runs into trillions of dollars annually, the report said.

For example, it suggested that the value of human welfare benefits provided by coral reefs was up to £109bn annually. The destruction of coral reefs is not only damaging to marine life but also poses risks to communities, the report said. Some 30 million people around the world rely on reef-based resources for food production, and for their livelihoods.

In another example, the report said that the economic value of insect pollinators, such as honey bees, in global crop production was £134bn a year.

Damage to natural capital including forests, wetlands and grasslands was valued at between $2trn and $4.5trn annually. But these figures are not included in economic data such as GDP, or in corporate accounts.

Now the hope is that with the IPBES, they will be taken into account, and a true picture of how much biodiversity loss is costing the world will emerge.

Original article –

Climate update : Is climate change to blame for famine in the Horn of Africa?

It’s impossible, says Duncan Green of The Guardian, to answer with a simple yes or no – but here’s a summary of what we think we know so far

So is famine in the Horn of Africa linked to climate change or not? The question arises whenever “extreme weather events” – hurricanes, floods, droughts – hit our TV screens. It’s impossible to answer with a simple yes or no – but here’s what we think we know so far.


The current drought conditions have been caused by successive seasons with very low rainfall. Over the past year, the eastern Horn of Africa has experienced two consecutive failed rainy seasons. According to surveys of local communities, this is part of a long-term shift. Borana communities in Ethiopia report that whereas droughts were recorded every six to eight years in the past, they now occur every one to two years.

Meteorological data back up the picture on temperatures: mean annual temperatures increased from 1960-2006 by 1C in Kenya and 1.3C in Ethiopia, and the frequency of hot days is increasing in both countries. Rainfall trends are less clear: according to the Intergovernmental Panel on Climate Change’s Fourth Assessment Report, there are no statistically significant trends in rainfall. However, more recent research suggests that rainfall decreased from 1980 to 2009 during the “long-rains” (March to June).

The historical record does not “prove” that the current drought is directly attributable to climate change. True, there are now a few cases in which scientists have been able to estimate the extent to which man-made climate change has made a particular extreme weather event more likely, but these exercises require reliable long-term weather data that only exists for Europe and North America – no such studies as yet exist in the case of the current drought.

What about the future? Globally, climate change modelling projects an increase in the frequency and severity of extreme weather events like droughts and floods. In the absence of urgent action to slash global greenhouse gas emissions, temperatures in the region will probably increase by 3C-4C by 2080-99 relative to 1980-99.

But again, rainfall projections are unclear. Most modelling, as reflected in the IPCC’s last assessment, suggests more rain will fall in the east Africa region as a whole, with an increase in “heavy events” (sudden downpours, so more flood risk). However, some recent studies suggest rainfall will decrease, particularly in the long rains.

The combination of higher temperatures and more unpredictable rains is alarming for food production. One recent estimate published by the Royal Society suggests much of east Africa could suffer a decline in the length of the growing period for key crops of up to 20% by the end of the century, with the productivity of beans falling by nearly 50%.

The conclusion? Attributing the current drought directly to climate change is impossible, but in the words of Sir John Beddington, the UK government’s chief scientific adviser, in a talk at Oxfam last week, “worldwide, events like this have a higher probability of occurring as a result of climate change”. Moreover, unless something is done, the current suffering offers a grim foretaste of the future – temperatures in east Africa are going to rise and rainfall patterns will change, making a bad situation worse.

What to do? First, remember that while the drought is caused by lack of rainfall, famine is man-made. As the Nobel prize-winning economist Amartya Sen famously observed, famines do not occur in functioning democracies. The difference between the minor disruption of hosepipe bans and the misery in the Horn is down to a failure of politics and leadership. It is no accident that the communities worst affected by the drought are not just those blighted by conflict but also by decades of official neglect and contempt from governments, which see pastoralism as an unwanted relic of the past.

Second, the famine shows the extreme vulnerability of poor people to weather events like failed rains. Governments and the international community have to save lives now, but also act to reduce that chronic vulnerability, building local ability to manage the drought cycle, improving the flow of data, information and ideas for adapting to climate change, and drastically increasing long-term investment in smallholder agriculture and pastoralism, which have shown they can provide a decent life for millions of east Africans, provided they are supported (rather than ignored) by governments.

Beyond helping east Africa and other vulnerable regions adapt to impending climate change, it is of course also incumbent on the rich and emerging economies to cut the greenhouse gas emissions that cause it. Fail to do that, and all attempts at adaptation are likely to offer only temporary relief.

• Oxfam last week published a briefing on climate change and drought in east Africa