New paleoclimatic perspectives on the future of terrestrial systems: bigger change, higher confidence?

June 14, 2017
WDG

Institute for Biodiversity & Ecosystem Dynamics seminar
University of Amsterdam
22 June 2017 (for details click here)

New paleoclimatic perspectives on the future of terrestrial systems: bigger change, higher confidence?
Jonathan Overpeck
The University of Arizona

Numerous assessments of future freshwater and terrestrial system change have highlighted the potential for unprecedented change in the 21st century given continued emissions of greenhouse gases (GHGs) to the atmosphere; the risk to biodiversity is also believed to be high. The basis for these assertions are strengthened by recent observed ecosystem change, as well as by a new global compilation of climate and vegetation change over the last deglaciation indicating that most, if not all, dominantly natural landscapes on the planet are at high risk of significant transformation given the projected magnitude of warming that is likely in the future absent major reductions in global GHG emissions. At the same time, new paleoclimatic results indicate that the Amazon forests may be more resilient to future change than previously thought, whereas the risk of human deforestation associated with multi-year “megadrought” might be higher than previously believed.  A growing body of literature highlight that drought and megadrought risk around the globe is going to be a bigger problem than widely thought. We know with great confidence that warming will continue as long as GHG emissions continue, and this means more drying of terrestrial systems is likely over much of the planet. As a result, droughts will become more severe, longer and frequent as long as GHG emissions are not reduced significantly. The ability of precipitation increases to mitigate the ecological and hydrological impacts of continued warming is especially diminished in the many regions of the globe where multi-decadal megadrought is likely, an assessment made more challenging by the growing realization that that state-of-the-art climate models may underestimate the risk of future megadrought. Existing global climate change assessments may thus be underestimating the challenges to terrestrial water and ecoystems under continued climate change.

Hosted by: William Gosling

Shining a light on fossil sunshine

December 15, 2016
WDG

Dr. Phil Jardine

Dr. Phil Jardine

An international team of scientists have reconstructed the longest ever record of past sunshine using pollen trapped in lake sediments collected in Ghana, Africa. The study published today in Scientific Reports enables us to understand past changes in solar input to the global system over the past 140,000 years. Previously we have had to rely upon computer models to mathematically determine past solar inputs to the Earth. “This work really is a first; being able to peer back in time to understand how the Sun has driven our global system over many of thousands of years is a very exciting prospect” said joint-lead author Dr. Phillip Jardine of The Open University.

The Sun is a key component of our natural environment, driving a multitude of processes at Earth’s surface, from photosynthesis generating energy within plants, through to global-scale circulation patterns in our oceans and atmosphere. Understanding more about how the Sun has behaved in the past, and the influence this had on Earth’s environment, will help scientists predict future climate change.

Dr. Jardine used a technique pioneered by one of his co-authors, Dr. Wesley Fraser of Oxford Brookes University, to determine past changes in solar input, specifically changes in ultraviolet (UV) radiation. Plants protect themselves from the harmful nature of ultraviolet radiation by incorporating a number of specific chemical compounds into their tissues that absorb and dissipate the energy of UV radiation. Pollen grains of flowering plants are also provided protection by these UV-absorbing chemicals, thus act as a long-term recorder of ultraviolet radiation from the Sun.

Pollen grains are readily trapped in lake sediments, where they can be preserved for millions of years. By extracting material from Lake Bosumtwi, Ghana, the pollen that was released by flowering plants thousands of years ago can be separated from the lake sediment and chemically analysed for UV-absorbing chemical compounds. It is this chemical signature within the ancient pollen grains that provides us with information about past levels of solar ultraviolet radiation.

“What we present here is a new opportunity to explore how the Earth has changed” said Dr. William Gosling (University of Amsterdam). “I am particularly excited about this because it will means that we can gain a better understanding of why vegetation changed in the past, and consequently this will allow us to anticipate better what the likely impacts of projected future climate change will be.”

This study is available now at www.nature.com/articles/srep39269

Jardine PE, Fraser WT, Lomax BH, Sephton MA, Shanahan TM, Miller CS & Gosling WD (2016) Pollen and spores as biological recorders of past ultraviolet irradiance. Scientific Reports. DOI: 10.1038/srep39269

Tropical forests in the Anthropocene

November 8, 2016
WDG

Yadvinder MalhiSeminar
Institute for Biodiversity & Ecosystem Dynamics
University of Amsterdam

Tropical forests in the Anthropocene
by Prof. Yadvinder Malhi (University of Oxford)

16:00-17:00, 24 November 2016
Science Park, Amsterdam
If you want to attend please click here for full details.

ABSTRACT: Continue Reading

Biodiversity and global change in the tropics

November 7, 2016
WDG

Treub Maatschappij – Society for the Advancement of Research in the Tropics
&
Institute for Biodiversity and Ecosystem Dynamics (IBED),University of Amsterdam

“Biodiversity and global change in the tropics”

Coordinators: Carina Hoorn & W. Daniel Kissling
Time: Thursday 17 November 2016, 13:30-17:00
Location: University of Amsterdam, Science Park (click here for link to registration)

PROGRAMME Continue Reading

Hall, S.A. (2010) Early maize pollen from Chaco Canyon, New Mexico, USA. Palynology 34, 125-137. DOI: 10.1080/01916121003675746

Janzen, D.H. (1967) Why mountain passes are higher in the tropics. The American Naturalist 101, 233-249. DOI: 10.1086/282487

Tovar, C., Arnillas, C.A., Cuesta, F. & Buytaert, W. (2013) Diverging responses of tropical Andean biomes under future climate conditions. PLoS ONE 8, e63634. DOI: 10.1371/journal.pone.0063634

Shanahan, T.M., Hughen, K.A., McKay, N.P., Overpeck, J.T., Scholz, C.A., Gosling, W.D., Miller, C.S., Peck, J.A., King, J.W. & Heil, C.W. (2016) CO2 and fire influence tropical ecosystem stability in response to climate change. Scientific Reports 6, 29587. DOI: 10.1038/srep29587

Bush, M.B. & McMichael, C.N.H. (2016) Holocene variability of an Amazonian hyperdominant. Journal of Ecology online. DOI: 10.1111/1365-2745.12600

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