Saturday round-up: Global warming “undeniable”

Ten indicators with increasing or decreasing values that demonstrate that the planet is warming. Credit: NOAA

Institutions fighting climate change have this week come out guns blazing, with a review of climate indicators in 2009 providing the heaviest fire. Bringing together 300 authors from 48 countries, the US “State of the Climate Report 2009” highlights 10 climate indicators that clearly demonstrate warming.

“Despite the variability caused by short-term changes, the analysis conducted for this report illustrates why we are so confident the world is warming,” said Peter Stott, head of Climate Monitoring and Attribution at the UK’s Met Office Hadley Centre. He emphasises that it’s natural for there to be unpredictable changes from one year to the next, so it’s necessary to look at longer-term records. “When we follow decade-to-decade trends using multiple data sets and independent analyses from around the world, we see clear and unmistakable signs of a warming world,” Stott said.

When should we stop emitting?

Bob Kopp, AAAS science and technology policy fellow.

Bob Kopp says that we have good records showing that the amount of CO2 in the atmosphere is currently the highest it’s been in 800,000 years. He should know, as he is a paleoclimatologist – a scientist who studies climate change through Earth’s history. Beyond these higher-quality records that are trapped deep in the ice at our poles, lower quality evidence suggests that CO2 levels may even be the highest for 3 million years. “If we keep doing what we’re doing, then by the end of the century CO2 levels will probably be about as high as they have been in about 40 million years,” Kopp said. “40 million years ago, temperatures were on the order of 5-10ºC warmer than today and there weren’t permanent ice sheets on the planet.”

CO2 in the atmosphere takes time to have an effect on the rest of the climate, Kopp points out, so if we continued to emit as we are and then stopped, the warming would carry on for many years. “If we don’t stabilize [greenhouse gas concentrations] until after the end of the century, then we’ll be on track over the course of centuries, maybe at most a few millennia, to end up with a world that looks more like the world did 40 million years ago than it has since the human civilisation has grown up and thrived,” he said.

Saturday round-up: Marmots relish long, hot, summers

A yellow-bellied marmot pup. Credit: Raquel Monclus

Global warming is proving positive for Colorado’s yellow-bellied marmots, according to research that improves on a previously poor understanding of how climate change is affecting species. Imperial College London’s Arpat Ozgul and his colleagues claim to show that changes in when the seasons happen can simultaneously change the body mass and population size of a species for the first time. “Marmots are awake for only four to five months of the year,” explained lead author Ozgul. “These months are a busy time for them – they have to eat and gain weight, get pregnant, produce offspring and get ready to hibernate again. Since the summers have become longer, marmots have had more time to do all these things and grow before the upcoming winter, so they are more likely to succeed and survive.”

It is difficult to collect enough data to work out exactly how climate change affects plants and creatures’ lives. However, Ozgul and his colleagues from the Universities of Florida, Kansas, California and Sheffield, UK, took advantage of records of Colorado marmots dating back to 1962, focusing on the most complete data set from 1976-2008. Writing in leading scientific journal Nature on Thursday, the team also used a recently-developed method to analyse body masses and survival rates. They saw an abrupt increase in the proportion of adult marmots among the population and in the mass of those older marmots. “Marmots are now born earlier and they have more time to grow until the next hibernation,” the team writes. “This increase in juvenile growth has caused an increase in body mass in all age classes.”

Researchers fight for OK coral

Penn State University's Nick Polato. Credit: Penn State University.

“Unfortunately for corals the outlook is grim.” So says Nick Polato, a graduate student at Penn State University. “While some reefs will certainly endure, we are facing drastic declines both in the number and diversity of reefs as they deal with a host of man-made impacts, such as development and pollution, which aggravate effects of climate change.” Polato is a member of the team led by Iliana Baums, which last month had its research into the effect of temperature on young corals published in the journal PloS One. Polato points out that corals can’t move into more favourable environments except when they are in their young forms, known as larvae. “Our study showed high temperatures can really mess up the development of young corals,” he says, “so the ability of coral larvae to endure stress will be critical to the survival and recovery of affected reefs.”

Because corals don’t feature obviously in most people’s lives, it’s easy to underestimate their importance, Polato says. “Reefs matter because they protect shorelines from erosion, provide habitats for many species that we rely on for food, and that contain unique chemical compounds that we might be able to use to develop new drugs,” he explains. While he and his fellow researchers have looked at exactly how coral larvae respond to higher temperature, Polato emphasises that the loss of colour and death of mature coral has been well studied. “It is proven beyond reasonable doubt that corals bleach and eventually die in response to persistent warm water temperatures,” he says.

Saturday round-up: Tropical troubles?

Apparently healthy Diploastrea heliopora coral colony from the central Red Sea. CT scan analysis of annual growth bands revealed declining skeletal growth rates since 1998 in response to ocean warming. Credit: Science/AAAS

Seemingly-healthy coral off the coast of Saudi Arabia has in fact been stunted by consistently warm temperatures over the past decade, US researchers have found this week. “Should the current warming trend continue,” write Neal Cantin and his colleagues at the Woods Hole Oceanographic Institution, “this coral could cease growing altogether by 2070.”

Higher sea temperatures have increased coral bleaching and death, as the algae that lives within coral and provides it with energy and colour, is forced to leave or dies. Cantin’s team notes that the Red Sea has been 1.46°C warmer than the 1950–1997 average summer temperature over the past decade, compared with 0.4-1°C warming over the past four decades across all tropical and subtropical seas. Yet it has seen little coral bleaching, suggesting that the species that live there may be especially hardy.

We know what to do, but what happens if we don’t?

Does this child know what sort of future he's running towards? Credit: Indiana University

There’s a wall dead ahead, and you’re running towards it at speed. When do you slow down and change direction? One metre before the wall? 100 metres? Back a couple of miles ago when there was a sign saying you were headed for a dead end? Now what if you’ve been told that the wall is in fact a mirage?

I’ve been writing this blog for a little over six months now, and have heard from sixteen researchers who have been studying climate change and its effects. From what they say, and the other research I’ve covered, it currently seems unlikely that the results of climate change will be as instant as the result of a person running headlong into a brick wall. However they will be serious, and they do demand a shift in direction.

Saturday round-up: Hot enough for ya?

Stanford scientists project that from 2030 to 2039, most areas of Arizona, Utah, Colorado and New Mexico could endure at least seven seasons equally as intense as the hottest season ever recorded between 1951 and 1999. Credit: 'jhadow' via Flickr/Creative Commons

As New York reached record temperatures this week, Stanford researchers claimed that such events could become increasingly common over the next 30 years. “Using a large suite of climate model experiments, we see a clear emergence of much more intense, hot conditions in the U.S. within the next three decades,” said Stanford’s Noah Diffenbaugh.

Together with with co-author Moetasim Ashfaq, Diffenbaugh uses these results to suggest that the global warming threshold often seen as dangerous is too simple. That 2°C limit mainly comes from political negotiations, the scientists note in a Geophysical Research Letters paper published online ahead of printing last week. “The intensification of hot extremes reported here suggests that constraining global warming to 2°C above pre-industrial conditions may not be sufficient to avoid dangerous climate change,” they write.

Emitting CO2 puts seas in double trouble

Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland Credit: Ove Hoegh-Guldberg, Global Change Institute, University of Queensland

Humanity relies heavily on the ocean and its inhabitants, who man in turn is putting at risk by changing the climate. That’s according to Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, who points out that global warming and ocean acidification pose “serious threats to life in the ocean”. “Both of those are having profound effects on the biology of the ocean and on the ocean services which are important to human well-being,” he told Simple Climate.

In fact, some of these effects have happened so fast that Hoegh-Guldberg has seen them unfold during the course of his career. For example, corals are normally highly coloured, but have been turning white and dying as they lose the microorganisms that inhabit them and provide them with energy and food. “When I started my PhD in the early 1980s, mass coral bleaching events were just beginning to occur across tropical regions,” he explained. “We now know that those are being driven by warmer than normal sea temperatures and that they are slowly removing coral dominated communities from tropical reefs, at the rate of 1-2% per year. Given that this is the most biologically diverse ecosystem on the planet, I think that these rates are striking.”

Saturday round-up: Cutting emissions, teacup by teacup

Heavily CO2 emitting coal-fired power stations like these are likely to supply the electricity to boil your kettle. And like your kettle, those power stations produce steam, which are the clouds shown here, not CO2 or smoke. Credit: Imperial College.

Your kettle and the milk you put in your hot drink are actually both powerful weapons with which to slash greenhouse gas emissions, research has underlined this week. For example, the energy the kettle uses could produce up to 60% more greenhouse gas emissions than governments have been assuming, claims Imperial College’s Adam Hawkes. “This means any reduction we make in our electricity use could have a bigger impact on the amount of carbon dioxide emitted by power stations than previously thought,” Hawkes explained. “However, this also acts in reverse: a small increase in the amount of electricity we use could mean a larger increase in emissions than we previously thought, so we need to make sure we do everything we can to reduce our electricity use.”

Hawkes studied emissions in the UK from 2002 to 2009, where the government estimates that CO2 emissions are 0.43 kilograms per kilowatt hour. That figure comes from averaging the amount of emissions produced by each different type of power source, a method commonly adopted across the world. However this ignores the fact that in the UK sudden changes in electricity demand are mainly met by coal-fired power stations, which produce lots of CO2. “A change in demand does not act upon all elements of the electricity system proportionally,” Hawkes wrote in a paper published in the journal Energy Policy last Tuesday.