A team of more than 100 scientists has assessed the impact of global warming on thousands of tree species across the Amazon to discover the winners and losers from 30 years of climate change. Their analysis found the effects of climate change are altering the rainforest's composition of tree species but not quickly enough to keep up with the changing environment.
The team, led by University of Leeds in collaboration with more than 30 institutions around the world, used long-term records from more than a hundred plots as part of the Amazon Forest Inventory Network (RAINFOR) to track the lives of individual trees across the Amazon region. Their results found that since the 1980s, the effects of global environmental change - stronger droughts, increased temperatures and higher levels of carbon dioxide in the atmosphere - has slowly impacted specific tree species' growth and mortality
In particular, the study found the most moisture-loving tree species are dying more frequently than other species and those suited to drier climates were unable to replace them. ... The species most vulnerable to droughts are doubly at risk, as they are typically the ones restricted to fewer locations in the heart of the Amazon, which make them more likely to be extinct if this process continues.
Climate Change Causing More Severe Wildfires, Larger Insect Outbreaks In Temperate Forests
A warmer, drier climate is expected is increase the likelihood of larger-scale forest disturbances such as wildfires, insect outbreaks, disease and drought, according to a new study co-authored by a Portland State University professor.
The study, published Oct. 19 in the journal Nature Communications, sought to provide a more complete snapshot of disturbances in the world's temperate forests by quantifying the size, shape and prevalence of disturbances and understanding their drivers.
The study found that while many temperate forests are dominated by small-scale disturbance events -- driven largely by windstorms and cooler, wetter conditions -- there was also a strong link between high disturbance activity and warmer and drier-than-average climate conditions. Andrés Holz, a co-author and geography professor in PSU's College of Liberal Arts and Sciences, said this suggests that with a warming climate, disturbances are expected to become larger and more severe in some temperate forests including the western U.S.
"Under the warmer conditions we have been seeing, it is likely that we're going to see a higher probability of areas that tend to have very big disturbances," he said.
New Research Questions the Rate of Climate Change
Climate change may be occurring even faster than first thought.
That is according to a ground-breaking new study by Dr Clayton Magill from the Lyell Centre at Heriot-Watt University.
Scientists measured the vast migration of sea bed materials such as clay and sand, a process that occurs over thousands of years.
The research found that constant movement resulted in the erosion of ancient fossils trapped within the ocean floor and that these fossils release their harmful carbon dioxide, which is a strong greenhouse gas. Researchers previously thought that the rate of erosion on these fossils was significantly slower – hence climate change was slower.... “We don’t know how much carbon is trapped in the ocean but now we’ve proven the process, it could pose catastrophic threat to earth’s climate.”
Our results suggest differential lateral transfer dynamics can influence apparent lead–lag patterns among proxies with differing grain-size associations.
Open Source: Clayton R. Magill et al. Transient hydrodynamic effects influence organic carbon signatures in marine sediments, Nature Communications (2018)
AbstractOcean dynamics served an important role during past dramatic climate changes via impacts on deep-ocean carbon storage. Such changes are recorded in sedimentary proxies of hydrographic change on continental margins, which lie at the ocean–atmosphere–earth interface. However, interpretations of these records are challenging, given complex interplays among processes delivering particulate material to and from ocean margins. Here we report radiocarbon (14C) signatures measured for organic carbon in differing grain-size sediment fractions and foraminifera in a sediment core retrieved from the southwest Iberian margin, spanning the last ~25,000 yr. Variable differences of 0–5000 yr in radiocarbon age are apparent between organic carbon in differing grain-sizes and foraminifera of the same sediment layer. The magnitude of 14C differences co-varies with key paleoceanographic indices (e.g., proximal bottom-current density gradients), which we interpret as evidence of Atlantic–Mediterranean seawater exchange influencing grain-size specific carbon accumulation and translocation. These findings underscore an important link between regional hydrodynamics and interpretations of down-core sedimentary proxies.
