How I feel now about climate change

10 03 2020

‘Bleak No. 2’ by David Vogler

Five years ago I was asked by a researcher at the Australia National University, Joe Duggan, how I ‘felt’ about climate change.

This was part of an original initiative that put a human face on the scientists working on elements of one of society’s greatest existential threats.

Thus, Is This How You Feel? became a massive success in terms of bringing to the world the idea that scientists are also deeply affected by what they see happening around them.

Five years later, Joe asked me and all the other scientists who participated to provide an update on how we feel.

Here’s what I wrote: Read the rest of this entry »

Cartoon guide to biodiversity loss LIX

24 02 2020

The second set of six biodiversity cartoons for 2020. See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.

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Cartoon guide to biodiversity loss LVIII

4 01 2020

The first set of six biodiversity cartoons for 2020. This special, Australia-is-burning-down-themed set is dedicated to Scott Morrison and his ilk. See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.

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Did people or climate kill off the megafauna? Actually, it was both

10 12 2019

When freshwater dried up, so did many megafauna species.
Centre of Excellence for Australian Biodiversity and Heritage, Author provided

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Earth is now firmly in the grips of its sixth “mass extinction event”, and it’s mainly our fault. But the modern era is definitely not the first time humans have been implicated in the extinction of a wide range of species.

In fact, starting about 60,000 years ago, many of the world’s largest animals disappeared forever. These “megafauna” were first lost in Sahul, the supercontinent formed by Australia and New Guinea during periods of low sea level.

The causes of these extinctions have been debated for decades. Possible culprits include climate change, hunting or habitat modification by the ancestors of Aboriginal people, or a combination of the two.

Read more: What is a ‘mass extinction’ and are we in one now?

The main way to investigate this question is to build timelines of major events: when species went extinct, when people arrived, and when the climate changed. This approach relies on using dated fossils from extinct species to estimate when they went extinct, and archaeological evidence to determine when people arrived.

Read more: An incredible journey: the first people to arrive in Australia came in large numbers, and on purpose

Comparing these timelines allows us to deduce the likely windows of coexistence between megafauna and people.

We can also compare this window of coexistence to long-term models of climate variation, to see whether the extinctions coincided with or shortly followed abrupt climate shifts.

Data drought

One problem with this approach is the scarcity of reliable data due to the extreme rarity of a dead animal being fossilised, and the low probability of archaeological evidence being preserved in Australia’s harsh conditions. Read the rest of this entry »

Climate change and humans together pushed Australia’s biggest beasts to extinction

25 11 2019

people-megafaunaOver the last 60,000 years, many of the world’s largest species disappeared forever. Some of the largest that we generally call ‘megafauna’ were first lost in Sahul — the super-continent formed by the connection of Australia and New Guinea during periods of low sea level. The causes of these extinctions have been heavily debated for decades within the scientific community.

Three potential drivers of these extinctions have been suggested. The first is climate change that assumes an increase in arid conditions that eventually became lethal to megafauna. The second proposed mechanism is that the early ancestors of Aboriginal people who either hunted megafauna species to extinction, or modified ecosystems to put the largest species at a disadvantage. The third and most nuanced proposed driver of extinction is the combination of the first two.

The primary scientific tools we scientists use to determine which of these proposed causes of extinction have the most support are dated fossil records from the extinct species themselves, as well as archaeological evidence from early Aboriginal people. Traditionally, the main way we use these data is to construct a timeline of when the last fossil of a species was preserved, and compare this to evidence indicating when people arrived. We can also reconstruct climate patterns back tens of thousands of years using models similar to the ones used today to predict future climates. Based on the comparison of all of these different timelines, we conclude that abrupt climate changes in the past were influential if they occurred at or immediately before a recorded extinction event. On the other hand, if megafauna extinctions occur immediately after humans are thought to have arrived, we attribute more weight to human arrival as a driver.

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Logbook of Australia’s ancient megafauna

20 11 2019


Australia is home to some of the most unique species worldwide, including egg-laying mammals, tree-climbing, desert-bouncing and and burrow-digging marsupials, and huge flightless birds. While these animals are fascinating, the creatures that used to roam Australia’s landscape thousands of years ago were even more remarkable — these included wombat-like beasts as big as rhinos, birds more than two metres tall, lizards more than seven metres long, and a marsupial lion as big as a leopard.

Just how and why these animals went extinct has been challenging scientists for decades. But examining dated fossil records is one of the primary ways we can look into the past. The ever-increasing number of fossils and the advances in dating techniques have produced a wealth of material we can use to reconstruct the long-lost past.

DiprotodonEven with these data, it has been a struggle to gather enough fossils for large-scale analyses because reports of these records are usually scattered across the scientific literature, with no standardised quality control to make them comparable to each other. Designing a way to standardise these records is therefore important to avoid misleading conclusions.

The FosSahul database was first established in 2016 to try to alleviate these problems — it gathered all the fossil specimens for large animals (excluding humans) from the Late Quaternary (up to ~ 1 million years before present) across the region known as ‘Sahul’, the combined super-continent that included New Guinea and Australia when sea levels were much lower than they are today.

While FosSahul was an important step, the database needed to be updated. First, the quality rating of the fossil dates in the original version was a little subjective and lacked transparency in some cases. This is because the database did not capture enough detail to be able to reproduce all the steps leading to a particular quality rating. Second, given that new fossils are discovered regularly, updates are necessary to include the latest research. Read the rest of this entry »

The politics of environmental destruction

22 10 2019

C_SE 409521698 Paul Ehrlich Lecture Event - Eventbrite2

You’d think I’d get tired of this, wouldn’t you? Alas, the fight does wear me down, but I must persist.

My good friend and colleague, the legendary Professor Paul Ehrlich of Stanford University, as well as his equally legendary wife, Anne, will be joining us in Adelaide for a brief visit during their annual southern migration.

Apart from just catching up over a few good bottles of wine (oh, do those two enjoy fine wines!), we have the immense privilege of having Paul appear at two events while he’s in town.

I’m really only going to be talking about the second of the two events (the first is a Science Meets Parliament gig with me and many others at the South Australia Parliament on 12 November): a grand, public lecture and Q&A session held at Flinders University on Wednesday, 13 November.

Haven’t heard of Paul? Where have you been hiding? If by some miracle you haven’t, here’s a brief bio:

Paul Ehrlich is Bing Professor of Population Studies Emeritus, President of the Center for Conservation Biology, Department of Biology, Stanford University and Adjunct Professor, University of Technology, Sydney. He does research in population biology (includes ecology, evolutionary biology, behavior, and human ecology and cultural evolution). Ehrlich has carried out field, laboratory and theoretical research on a wide array of problems ranging from the dynamics and genetics of insect populations, studies of the ecological and evolutionary interactions of plants and herbivores, and the behavioral ecology of birds and reef fishes, to experimental studies of the effects of crowding on human beings and studies of cultural evolution, especially the evolution of norms. He is President of the Millennium Alliance for Humanity and the Biosphere and is author and coauthor of more than 1100 scientific papers and articles in the popular press and over 40 books. He is best known to his efforts to alert the public to the many intertwined drivers that are pushing humanity toward a collapse of civilization – especially overpopulation, overconsumption by the rich, and lack of economic, racial, and gender equity. Ehrlich is a Fellow of the American Academy of Arts and Sciences, the American Entomological Society and the Beijer Institute of Ecological Economics, and a member of the United States National Academy of Sciences and the American Philosophical Society.  He is a Foreign Member of the Royal Society, an Honorary Member of the British Ecological Society and an Honorary Fellow of the Royal Entomological Society.  Among his many other honours are the Royal Swedish Academy of Sciences, Crafoord Prize in Population Biology and the Conservation of Biological Diversity (an explicit replacement for the Nobel Prize); a MacArthur Prize Fellowship; the Volvo Environment Prize; UNEP Sasakawa Environment Prize; the Heinz Award for the Environment; the Tyler Prize for Environmental Achievement; the Heineken Prize for Environmental Sciences; the Blue Planet Prize;  the Eminent Ecologist award of the Ecological Society of America, the Margalef Prize in Ecology and Environmental Sciences, and the BBVA Frontiers of Knowledge Award in Ecology and Conservation Biology. Prof Ehrlich has appeared as a guest on more than 1000 TV and radio programs; he also was a correspondent for NBC News. He has given many hundreds of public lectures in the past 50 years.

I hope your jaw just dropped.

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