Stored ocean heat will be released for centuries to come
Warming of at least 1.5 degrees Celsius over most of Earth’s land areas is probably already locked into the climate system — even if greenhouse gas concentrations were capped at today’s levels.
The new climate change warning came from UK scientists who, in a new study, differentiated between the warming over land areas and the average global temperature increases often used in discussions about efforts to limit emissions of CO2 and other greenhouse gases.
“Millions of people around the world should be receiving heat-related warnings and advisories if we are to avoid a repeat of the thousands of deaths which occurred last year from heatwaves notably in Asia and Europe,” said Robert Glasser, the UN Secretary-General’s special representative for disaster risk reduction.
“More effort is required to ensure that the poor and vulnerable including refugees, children, older persons and persons living with disabilities are reached with early warnings and that practical measures are taken to ensure they have access to water and adequate shelter and protection from the heat and the sun,” Glaser said, adding that emergency service managers need to “step up the focus on extreme heat” to reduce mortality. Continue reading “UN warns of heatwave health risks”→
Migration changes could affect competition for nesting sites
As global warming speeds up the springtime northward migration of swallows, it could spell trouble for mountain bluebirds.
Both species are cavity nesters; at times they compete for the same habitat. Historically, mountain bluebirds have arrived in the breeding territories earlier than the swallows, giving them a chance to defend their nests. But if the swallows arrive first, the bluebirds may have a harder time finding a safe spot to lay eggs, according to new research published in The Auk: Ornithological Advances.
The scientists from the University of Saskatchewan acknowledged that the outcomes of interspecies battles for nest sites depend on a number of factors, but wanted to study what happens when tree swallows and mountain bluebirds compete for nest sites. So they set up side-by-side pairs of nest boxes in grassland habitat in central British Columbia.
When bluebird and swallow pairs moved in next door to each other, they would either block the entrance to one box and let the two pairs of birds compete for the one that remained, or remove both boxes and replace them with a fresh one.
“I became interested in this topic after watching many competitive interactions over natural tree holes during a long-term study of Northern Flickers in central British Columbia,” said researchers Karen Wiebe. “In early spring when the birds are trying to claim a nest site, these disputes can be intense and really grab your attention. Because bluebirds and swallows readily use nest boxes, I was motivated to try some experiments in a system where I could have more control over the spacing of nests and settlement patterns of the birds.”
Wiebe found that when Tree Swallows were defending their previously owned box or when the two species were competing over a new box, Tree Swallows won 65-70 percent of the time. Bluebirds got a boost when they defended a box they already occupied, however, fending off swallows 77 percent of the time.
Climate change may bring the two species into direct competition more often and reduce bluebirds’ ability to claim and defend nest sites.
“This is a nice set of clever and simple experiments that show that species are not the same when it comes to the importance of being the first one to occupy a nest site,” according to ecologist Hanna Kokko of the University of Zurich, an expert on interspecies competition in birds. “The one that currently tends to arrive first, the bluebird, relies more on this, which could easily cause problems if the arrival order changes on a changing planet.”
New study suggests tropical storms will become more intense
Tropical storms may become less frequent as the planet warms up, but those that do form could be increasingly powerful, according to a new study published in the journal Science last week.
How global warming will affect tropical storm formation in the decades ahead has been the subject of intensive research. The new study says that, so far, the warming effects of greenhouse gases on tropical cyclones have been hard to discern because of natural variability and also because air pollution has been masking the impacts. Continue reading “Will global warming super-charge hurricanes?”→
British researchers say regional patterns of melting of glaciers on the Antarctic Peninsula are linked with warming oceans in the region. The Antarctic Peninsula is one of the biggest contributors to sea level rise, so the new finding will help pinpoint how fast and how high seas will rise in the decades ahead.
Many bird species could lose between 78 and 85 percent of their existing habitat
Birds and reptiles in the Southwest that live in fragmented habitat will be hit hardest by global warming in the decades ahead, according to a new study by scientists with the U.S. Geological Survey and the Northern Arizona University.
The researchers took a close look at about 30 different animals, including well-known species such as the Gila monster, horned lizard, chuckwalla, Sonoran desert tortoise, pinyon jay, pygmy nuthatch, sage thrasher and black-throated sparrow.
After studying the impacts of recent droughts in the Amazon, researchers are warning that the rainforest may gradually be losing its ability to remove carbon from the atmosphere. But their study also shows that the ecosystem is resilient and can recover quickly in between droughts.
The study used data from from droughts in 2005 and 2010, finding that tree growth slowed across the vast forests of the Amazon Basin. Long-term measurements from theRAINFOR network spanning nearly a hundred locations across the Amazon Basin helped show how the rainforest temporarily lost biomass. Both droughts killed many trees, but the 2010 drought also had the effect of slowing the growth rates of the survivors, suggesting that many trees were adversely affected but not to the point of death. Continue reading “Droughts slow Amazon carbon uptake”→