Climate change set to bring Western Europe more hurricanes

In January 2009 a cyclone called Klaus, which is shown here and boasted hurricane-force winds, hit France, Spain and Italy. Such conditions could become much more common in Europe by the end of the 21st century, according to Rein Haarsma and his KNMI team. Credit: H de C via Flickr Creative Commons license

Current once-in-a-century hurricane-force winds may become as much as 25 times as likely in parts of Western Europe at the end of the 21^st century. That’s what Rein Haarsma and a team from the Royal Netherlands Meteorological Institute (KNMI) have shown using one of the highest-resolution climate models around today. Their findings spring from a change in where hurricanes will develop that could also affect western North America, though more research is needed to study this. “The statement that the wind climate in Western Europe will not change significantly is questionable,” Rein told me. “Significant changes in wind climate will have consequences for agriculture – the increased winds are during the autumn – infrastructure and coastal defence.”

With Europe so far from the tropical regions where warmth and unstable atmosphere spawns hurricanes, it rarely sees them today. But when hurricane conditions do happen, like the ‘Great Storm’ in 1987, or Hurricane Floyd in 1993, they live long in the memory. The hurricane remnants that sometimes reach Western Europe usually bring a lot of rain, Rein noted, and only occasionally hurricane-force winds.

The warming Arctic is reducing ocean temperature differences that help create Europe’s traditional storms, meaning they pose less of a threat. But recently findings have shown that a warmer atmosphere raises hurricane risks. “Many model simulations suggest that the strength of hurricanes will increase due to climate change,” Rein explains. “The area where hurricanes develop appears to move poleward and the moisture content in a warmer atmosphere will increase. These factors might alter the possibility that these remnants of hurricanes are still strong enough to produce hurricane-force winds.”

Iconic authors help reveal record early flowering

“When I wrote the following pages, or rather the bulk of them, I lived alone, in the woods, a mile from any neighbor, in a house which I had built myself, on the shore of Walden Pond, in Concord, Massachusetts, and earned my living by the labor of my hands only.” Those are the famous opening lines to Henry David Thoreau’s Walden. Now, scientists have used Thoreau’s notes on his surroundings to show how much earlier global warming has pushed plant flowering. Credit: Tim Hettler, via Flickr

Notes from the last 150 years made by two environmental pioneers have helped show that the speed at which global warming is pushing spring events forward is not slowing. Boston University’s Libby Ellwood and her teammates compared flowering times recorded by Henry David Thoreau and Aldo Leopold to spring 2010 and 2012, the warmest and second warmest on record.  “Plants flowered earlier than ever before in these recent record warm years,” Libby told me. That advance is so closely linked to the warming our world’s experiencing, the researchers showed that they can predict flowering time from temperature. This knowledge could help predict climate change’s impact on crops.

“There will likely be winners and losers with climate change,” Libby said. “It is quite possible that some species will be able to use the warmer temperatures and longer growing season to their advantage. The risk for plants that begin growing as soon as the weather is warm though, is that the new spring growth and flowers are susceptible to late season frosts, and this can set back plant growth and reproduction.”

To understand what global warming is doing to other organisms, scientists have to find records about them from times when fossil fuel burning wasn’t as widespread as today. Thoreau and Leopold are best known as authors of books that lay the foundations of modern environmentalism. Both Thoreau’s Walden and Leopold’s A Sand County Almanac, published in 1854 and 1949 respectively, hold powerful ideas on the relationship between humans and nature. But both authors also studied phenology – the cycle of biological events such as plant flowering throughout the year.

Warming brings home the value of a meal

The 2012 Plant Hardiness Zone Map unveiled by the US Department of Agriculture this year shows average annual extreme minimum temperatures based on data from 1976-2005. In this version 2012 is modified to use the same colour code as 1990. Much of the US was one 5°F (2.8°C) half-zone colder in the 1990 Plant Hardiness Zone Map compared to the latest version. Credit: US Department of Agriculture/Friend of the Earth

Part one of two

Over the past few days I’ve been lucky enough to enjoy the kind of celebrations that would have been called feasting in the past. They’ve brought home how important food is as basic fuel, a source of pleasure and a reason for friends and family to get together. This year, that importance has drawn me increasingly to research into what climate change means for our food supply. What I’ve covered only begins to scrape the surface of the effects we can expect. However, these studies highlight how life could become yet harder for farmers, and what that could cost us all.

The warming world has already noticeably changed plant growing conditions, for example shifting the regions they are suited to grow in the US. In January, the US Department of Agriculture (USDA) redrew its map of planting zones to reflect warming seen since the 1990 version. Partly due to climate change, and partly due to new technology and better weather data, many places are now one 5°F (2.8°C) half-zone warmer. At around the same time, Chinese researchers found that the phases in the seasonal cycle of crop growth in their country had shifted between 1960 and 2008. Springtime events are now 6-15 days earlier and Autumn events 5-6 days later, they found.

2012’s record events put climate in mind

Extent of surface melt over Greenland’s ice sheet on July 8 (left) and July 12 (right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. In the image, the areas classified as “probable melt” (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected surface melting. The satellites are measuring different physical properties at different scales and are passing over Greenland at different times. As a whole, they provide a picture of an extreme melt event about which scientists are very confident. Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory

This has been another year of striking climate events and records – but they seem to be happening so much more often today that their effect on me has weakened. That’s pretty cold-hearted, I admit. ‘Extreme weather’ is having terrible effects on peoples’ lives all around the world. But the truth is that we can only handle so many problems before becoming too numbed and overwhelmed to act. And last year, Stefan Rahmstorf and coworkers at the Potsdam Institute for Climate Impact Research showed temperature records are much more likely today than in a stable climate. “I don’t think many people appreciate how much the odds for such extremes have increased due to global warming,” he told me at the time. “I certainly didn’t until we had performed this study.” So it’s hardly surprising if we begin to get complacent when records are flowing thick and fast. But when I actually faced up to what’s happened in the climate this year, it was intriguing how well you could see global warming’s fingerprint.

Warming’s most dramatic effects have long been obvious in the Arctic, and 2012 was no different. Images from three satellites showed that almost Greenland’s entire ice sheet surface was temporarily melted by July 12. That’s the largest area in over 30 years of satellite observations. Then, on September 16, sea ice in the Arctic reached a record annual minimum area of 1.32 million square miles, approximately half the size of the average annual minimum for 1979 to 2000. Just two weeks later, Antarctic sea ice covered its highest area on record at the peak of winter, at 7.49 million square miles. In case you think that’s a natural balance that shows the planet isn’t warming, it’s worth noticing the scale of the changes. The Antarctic record is 193,000 square miles higher than its average maximum area for the last 30 years. That’s much less than the 1.32 million square miles the Arctic lost compared to its long-term average.

Monsoon instability raises food questions for India

A street in Calcutta floods during monsoon season. After some decades of increasing rainfall, climate change could bring drier monsoons, said Jacob Schewe from the Potsdam Institute for Climate Impact Research. Credit: Mark E Dyer/Flickr

Monsoon rains in India may fail more frequently as climate change proceeds into the 22^nd century, German researchers said this week. That danger could be critical for farming in what is set to become the world’s most highly populated country by 2030, and would follow an already expected wetter period. “Previous studies showed that Indian monsoon rainfall would increase more or less linearly with global warming over the next century,” said Jacob Schewe from the Potsdam Institute for Climate Impact Research. “The monsoon can respond to climate change in a more complicated way. We’ve seen that it matters to look further into the future.”

In South Asia, summer monsoon rains fall as winds blow from the southwest Indian Ocean over the continent between June and September. They end when the wind direction reverses in September or October. What Indian monsoon rain seasons will do as the world warms is an important and difficult question that many researchers are trying to answer. Though more rainfall has been predicted, recent years haven’t matched that expectation. While factors like pollution have an effect, changes climate scientists already know a major climate pattern plays a very important part in monsoons.

“There is a coupling between the El Niño Southern Oscillation and the monsoon that’s been observed for a long time,” Jacob told me. In years when El Niño occurs, an air movement pattern called the Walker circulation pattern gets shifted eastward. That brings high pressure over India and weakens the monsoon. While some changes in El Niño are already happening, the Walker circulation is expected to weaken, but not for some time yet. That could mean scientists’ climate models don’t pick up its effects. “People have looked at monsoon changes but not many studies have looked beyond 2100,” Jacob said. “You really have to consider longer timescales – beyond 2100 – to assess the full range of consequences for the monsoon.”

Climate provides weak power to predict African violence

Two boys from the Local Defence Unit (LDU) in Kitgum, Northern Uganda, whose job is to protect the people at a refugee camp from attacks and kidnappings by the Lord’s Resistance Army, which has been responsible for much violence in East Africa in recent years. Credit: John & Mel Kots/Flickr

Rainfall and temperature changes are linked to conflict in East Africa, but have less power to predict violence than links to political, economic and geographical factors. That’s according to one of the most detailed studies into climate-violence relationships yet, done by John O’Loughlin from the University of Colorado, Boulder, and his team-mates. “Fears of climate wars across Africa are exaggerated,” John told me. “Any effect of climate change will likely be localized and subject to other conditions.”

One political argument made about our changing climate is that it will bring more violence, particularly in Africa. For example, in 2009, US President Barack Obama told the United Nations that a warming world represents an “urgent, serious, and growing threat” because “more frequent drought and crop failures breed hunger and conflict”. But, with a background of looking in detail at where violence happens and having studied African conflicts before the 1990s, John was concerned that the evidence didn’t back such statements. That’s even though other researchers have reported statistical links between climate and conflict. “I believe that previous studies were limited by data problems and also that the policy discussions were not connected to the research findings,” John explained.

John’s team described how they fixed this in a paper published in the research journal Proceedings of the National Academy of Sciences of the USA on Monday. Previous attempts to study climate-violence have either lacked detail, looking at data per country, per year, or have been too narrowly focussed to allow generalisations, they wrote. John added that this type of work needs detailed data on both conflicts and all the factors that might predict it. Collecting the information needed on conflicts as well as political, health, location and other possibly predictive data was the biggest challenge in the work, he said.

Temperature rises could hamper developing world growth

Higher temperatures can lower productivity in non air-conditioned factories like this one owned by bead manufacturer Kazuya in Nairobi, Kenya, says MIT’s Ben Olken. Credit: Amy the Nurse/Flickr

Higher temperatures play a role in economic progress that brings bad news for poorer countries. Their development efforts may be slowed as the world warms further, suggest researchers at the Massachusetts Institute of Technology (MIT) and Northwestern University in Evanston, Illinois. Looking at over 50 years of weather data, MIT’s Ben Olken and his colleagues showed that every 1°C temperature increase shaves 1.3 percent off a poor country’s growth, over the course of a given year. That can have a big impact, considering the World Bank projects that developing countries’ economies will grow by 5.4 percent in 2012. “The key points of our study for thinking about climate change are that a) the impact seems to be larger for poorer countries and b) there is at least the possibility that the economic magnitude of the costs of higher temperatures for poorer countries could be quite large,” he told Simple Climate.

People have been asking whether temperature influences how rich a country is for centuries, with historian Ibn Khaldun discussing it in his book Muqaddimah in 1377. But researchers are still trying to tease out the various ways it can play a part even today. Getting a grip on this subject becomes more important as the world warms in response to human CO2 emissions, Ben noted. “Given the interest in global climate change, the link between temperature and economic growth is clearly important to understand,” he said. “While there are many studies that try to simulate these impacts, we thought it was very important to try to look, historically, at what actually happens when it gets warmer. When we thought of doing this, we were very surprised that nobody had really done it before.”

Ben, MIT’s Melissa Dell and Northwestern’s Ben Jones brought together temperature, rainfall and economic output data for 1950-2003 from 125 countries. In a paper published in the July edition of the American Economic Journal: Macroeconomics they compared temperature and rainfall changes against economic growth. By studying year-to-year changes they could avoid assumptions about what links exist and remove the effects of unchanging national factors. Looking at economic growth both in the same year as the weather data and up to ten years later allowed them to see how long any impacts lasted. While economic growth in poor countries was affected by temperature, there was little effect on growth in rich countries. Changes in rainfall have relatively mild effects on national growth in both rich and poor countries. Their data showed that these were permanent effects on growth, rather than temporary dips in output after which the countries continued the progress they were making before.

CO2-focused breeding can arm crops for food fight

Growth of modern farmed rice varieties rise proportionally less when CO2 levels go up than wild types. Lewis Ziska and his colleagues said that more effort needs to be made in plant breeding to make sure crops benefit from higher CO2 levels. Credit: Héctor de Pereda/Flickr

While CO2 emissions from humans burning fossil fuels are wrapping the world in a worryingly warming blanket, they could also help make our crops grow faster. But more direct effort is needed to make the most of this chance, say Lewis Ziska from the US Department of Agriculture and an international team of scientists. “Plant breeders often assume that on-going breeding efforts, for example for pest or disease resistance, would by themselves lead to adaptation to any rise in background CO2 levels,” Lewis told Simple Climate. “We’ve shown that this is not the case.”

Throughout the 20^th century crop breeding has been one part of a green revolution that has made farmers today able to produce much more food from their fields. But Ziska notes that these improvements in crop yields are slowing. Though climate change and the droughts it brings makes this problem even harder, the gas driving it could provide a way out.

“The gains of the green revolution with respect to population growth have ended,” Ziska said. “As agricultural scientists our goal is to ensure a safe and nutritious supply of food.  It is clear we will have to do so with fewer resources, specifically arable land, water and fertilizer. We have long recognized that CO2 is, by itself, a resource as it supplies plants with carbon, the basic building block for growth. Hence we are urging a systematic active effort in selecting cereal lines that could respond to rising CO2 levels by increasing their yields.”

This view springs from a wide range of evidence Ziska and his colleagues brought together in a paper published in the research journal Proceedings of the Royal Society B this week. This included Ziska’s own research showing how CO2 concentrations affected wheat bred during the 20^th century, when CO2 rose from around 290 parts per million (ppm) to 380 ppm. That study showed that higher CO2 concentrations increased the amount of wheat produced by forms developed nearer to 1900 more than modern varieties.

Continued emission growth promises US megadroughts

Pinyon pine forests that usually absorb CO2 from the atmosphere to grow near Los Alamos, N.M., in the region Christopher Schwalm and his colleagues studied, had already begun to turn brown from drought stress in the image at left, in 2002, and another photo taken in 2004 from the same vantage point, at right, show them largely grey and dead. Credit: Craig Allen, U.S. Geological Survey

Though the last time western North America saw a drought as severe as the one it experienced in 2000-2004 was 800 years ago, such conditions could become normal by the end of the century. This drying will shift western North America’s natural carbon cycle into reverse, from absorbing CO2 overall today to emitting it and worsening climate change further. That’s according to a paper by Christopher Schwalm, from Northern Arizona University in Flagstaff, and his colleagues published in the research journal Nature Geoscience on Sunday. “What we now call a drought event will become an abnormally wet episode by the end of the 21st Century,” Christopher told Simple Climate.

With drought in the US Midwest currently drawing much attention, the 2000-2004 drought might have slipped from some memories – even though they led to a natural disaster being declared in some areas. Our views of these events are bound to change as droughts become more regular as the world heats up, even though warmer air can contain more water vapour. “The changing climate means that the atmosphere can carry more water,” Christopher said. “However, precipitation will happen in spurts, more intensive rainfall in a relatively short period of time. Similarly, the amount of time between such events is expected to increase. So we will see fewer but more intense rainfall events, and therefore more droughts.”

The “turn of the century” drought has been remembered and closely studied by researchers looking at what it tells us about our climate. However, that research hasn’t been brought together to understand what it means for how much carbon plants are taking up, Christopher said. So he set out with a team of nine other US and Canada-based researchers to fill that gap. But to do so meant working with several sets of measurements that covered different areas and time periods. “Despite having various satellite data sources, global monitoring networks, and the like, our biggest challenge was how to piece together what data we do have and still paint a comprehensive picture,” Christopher explained.

Beefing down farming could cut carbon

University of Exeter’s Tom Powell. Credit: University of Exeter

If people like me in the developed world eat less steak, it could free up room for plants to reduce CO2 levels in the air driving climate change. That’s one forecast that has come from Tom Powell and Tim Lenton at the University of Exeter, who have studied how much space we’ll need for food in the future. “The impact on the environment of trying to produce the food demanded by the world’s population in the future could be disastrous, unless we make the production system much more efficient,” Tom told Simple Climate. “By far the easiest way to do this would be to cut meat eating, especially beef. Meat is likely to get more expensive as the resources needed to produce it become limited, and its environmental impact grows. Small changes to our diets and the ways we produce food have the potential to make what is currently a very environmentally damaging system a much more positive one.”

When we’re buying food, its climate impact may not be immediately obvious. But plants use the sun’s energy to take CO2 out of the atmosphere as they grow, storing that energy and CO2 in their bodies for a comparatively short time. “We can’t escape the links between our energy use, whether it’s for diet, industry or transport, and the carbon cycle,” Tom underlined. “Unfortunately, the carbon cycle also controls a sort of global thermostat, with the amount in the atmosphere as CO2 or methane influencing the climate.”

Tim and Tom noted that as the number of us on the planet grows, and we get wealthier, we are demanding more energy, both as food and fuel. “This is having damaging effects on ecosystems, and even on the world’s climate as the population grows toward 9.5 billion people all aspiring to a western lifestyle,” Tom underlined. As people get richer they also eat more meat – but meat production is hugely inefficient. Only about three or four parts in 100 of the feed energy livestock eat becomes food, with the rest lost as manure, heat, methane and slaughter by-products. Today, meat consumption provides one-sixth of the energy people across the world get from their food on average. However, people in rich countries eat much more meat, getting almost one third of their energy from it.