Humans are causing one of the worst mass extinctions in Earth history

Humans are the root cause of the ‘biological annihilation’ of life on Earth, according to a study published recently in the journal Proceedings of the National Academy of Sciences (PNAS).

The study – conducted by a team of scientists from the National Autonomous University of Mexico and Stanford University – studied population and distribution trends for 27,600 vertebrate species across the globe and found that 32 per cent are decreasing dramatically in both numbers and geographic range.

This study adds to the burgeoning evidence that we are not only witnessing one of the planet Earth’s worst mass extinction events but that we all collectively have blood on our hands.

How do we know that the situation is so serious and that most species will not simply soldier on?

To fully appreciate the scale of this tragedy, we can place the past few centuries within the context of what we know about life during Earth’s 4,543 million-year long history.

Biodiversity in Earth’s ancient past

Generations of scientists from different disciplines – palaeontology, geology and geochemistry, for example – have devoted their lives to reconstructing how life and environmental conditions have changed and become intertwined over time.

A similarly devoted cohort of ecologists and other scientists have been studying modern day species, habitats and ecosystems, looking at the rate of loss of species over time.

Ecologists measure extinction directly in the field, while palaeontologists and other geoscientists do so by digging fossils and extracting evidence from geologic layers of known ages.

Although they use different methods and data, both fields focus on similar questions – What species are present? How many? How do they interact? What causes species to migrate, boom and die off?

The ‘Big 5’

Mass extinction events – the widespread loss of life on our planet in a short period of time – are quite unusual when compared to the gradual ‘background’ extinction rates from the likes of ecological competition, predation and other gradual changes.

We now know that five major extinction events have disrupted the course of life on Earth over the past 600 million years.

The so-called ‘Big 5’ were the end-Ordovician extinction event 443 million years ago (Ma); the Late Devonian event between 370 and 365 Ma; the end-Permian event 252 Ma; the end-Triassic event 201 Ma and the end-Cretaceous event 66 Ma.

Based on the fossil record before and after these events, it is estimated that each of the ‘Big 5’ killed off at least 75 per cent of all life at that time.

These mass extinction events span intervals ranging from a few thousand to hundreds of thousands of years, a blip in geologic time.

The end-Cretaceous event is the most well understood, thanks in large part to the work conducted by the Nobel Prize winning scientist Luis Walter Alvarez and his son Walter.

Along with colleagues, they identified an ‘extraterrestrial’ iridium layer in sedimentary strata from deposits of this age at sites around the globe.

The story became clear when scientists stumbled upon a large impact crater at the Yucatán Peninsula in Mexico – the end-Cretaceous MEE and the last days of the non-avian dinosaurs were brought about by an asteroid impact and the ensuing chain of events.

The Great Dying

The end-Permian extinction, aptly nicknamed ‘The Great Dying’ was the largest and most catastrophic of the ‘Big 5’.

It caused the staggering loss of 95 per cent of marine species and 70 per cent of terrestrial species in a geologic heartbeat – about 20,000 years – according to 2011 study published in Science.

The ‘Great Dying’ resulted from runaway climate change – with global temperatures 8°C warmer than previous – caused by the release of large amounts of CO2 and other greenhouse gases to the atmosphere.

The exact trigger is still debated but it seems likely that massive volcanic eruptions in what is now Siberia and methane released from destabilised deep sea gas hydrates are the primary culprits.

The combined effect would have been a complete change in atmospheric composition, with CO2­ concentrations probably about four or five times higher than today, depletion of oxygen in the oceans and massive sea level rise.

Humans on par with asteroids and mass volcanism

While there have likely been numerous other mass extinction events prior to 600 Ma, the last 600 million years documents the rise and evolution of animal and plant life and all of the trials and tribulations faced with living on Earth.

So how do the ‘Big 5’ compare with extinction since humans have been on the scene?

There is abundant fossil and archaeological evidence that humans have been a primary cause of animal extinction ever since we moved out of Africa between 50,000 and 100,000 years ago.

According to a 2017 study in the journal Nature, the widespread extinction of large terrestrial species has coincided with historical human migrations.

Terrestrial animal extinctions continued unabated to the point that by about 3,000 years ago, it is estimated that 50 per cent of large mammal species and 15 per cent of birds were extinct.

Since 1500 AD extinction rates accelerated as the Age of Exploration brought us to vast new lands.

The International Union for Conservation of Nature (IUCN) now estimates that 338 vertebrate species have gone extinct since 1500 AD.

A 2015 study in the journal Science Advances puts vertebrate extinctions at as much 100 times greater than the calculated background rate of 2 per 100 years.

The IUCN Red List – containing a database of described species and their conservation status – currently contains 80,000 species and almost 30 per cent are threatened with extinction.

Forty-one per cent of amphibians, 34 per cent of conifers, 33 per cent of reef-building corals, 25 per cent of mammals and 13 per cent of birds are currently threatened.

The spread of agriculture is the main driver for most of these losses, followed by the spread of urbanisation, logging, mining, the loss wildlife transport corridors, hunting and water pollution.

Hundreds of species and countless populations are being lost each year as a result of human activity and since countless species have yet to be described, much more are also likely threatened or threatened with extinction.

The Anthropocene and the Sixth Mass Extinction

The greatest mass extinctions in Earth history brought complex life to the very brink of existence in as little as a few thousand years.

Historical and modern pressures from human activity have driven large proportions of species to extinction or to the brink of extinction in a similar, if not more rapid, timeframe.

Scientists may debate whether we are on the cusp or in the middle of the sixth mass extinction and when exactly the Anthropocene geological epoch – where humans have left behind a global identifiable record in the geologic record – began.

Either way, the plight of most species on Earth has reached crisis level and is set to escalate in the coming years as the human population potentially balloons by another four billion by the end of the twenty-first century and climate change will play an increasingly greater role in species extinction.

Urgent conventional and proactive conservation approaches are needed, together with an unprecedented degree of engagement between stakeholders, scientists and policy makers.

 A version of this article appeared in the Green News on July 21st, 2017.
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Three years and six goals to meet targets in the Paris Climate Agreement

A grouping of climate change experts has published six goals that must be achieved by 2020 in order to meet the targets set out in the 2015 Paris Climate Agreement.

In a letter published in the journal Nature, the authors and co-signatories – represented by eminent scientists, business leaders, economists and NGO representatives – declared we must “overcome the risks of climate change” and “act boldly together”.

To meet the Paris Agreement target of limiting global temperature increases to 1.5°C above pre-industrial levels, the experts identified six key goals to be met by 2020:

  1. Renewable energy should make up 30 per cent of global electricity supply and no coal-fired power plants should be commissioned
  2. Three per cent of building and infrastructure stock should come from near-zero or zero-emission buildings each year
  3. Electric vehicles should make up 15 per cent of annual car sales, as well as a 20 per cent reduction in aviation emissions and 20 per cent increase in efficiency of heavy duty vehicles
  4. Policies should be enacted to shift land use from deforestation to reforestation and traditional agriculture to sustainable approaches. In doing so these lands would switch from being carbon sources to carbons sinks by 2030
  5. Carbon-intensive heavy industry should have plans in place to increase efficiency and be on a path to halve emissions by 2050
  6. $1 trillion dollars should be set aside annually for climate action initiatives

The authors choice of 2020 is significant for two reasons.

Firstly, with current global CO2 emissions at a staggering 41 gigatonnes per year, the goals of the Paris Agreement become essentially unattainable if emissions continue at this scale by 2020.

Secondly, 2020  marks the year when a country can formally withdraw from the Paris Agreement, as President Trump has already announced that the US will do.

Although the authors recognise that their goals are “idealistic at best [and] unrealistic at worst” and that the “political winds are blustery”, they remain optimistic.

“We are in the age of exponential transformation and think that such a focus will unleash ingenuity,” the letter reads.

For the first time in history there is almost unanimous international agreement that the risks associated with climate change are too great to ignore and that we must work urgently and collectively.

In many cases, solutions already exist and the transition to low-carbon technology is well underway in many sectors.

The global expansion of wind and solar energy will continue and the global sales of electric vehicles appear to be on the cusp of a rapid global expansion.

The past three years mark the first time that global emissions have stagnated while global GDP has grown, indicating that measures already adopted are beginning to have an effect.

While the recent G20 summit highlights the political and civil tension that exists at present, one clear positive outcome from the weekend’s meeting was the reaffirmed commitment to the Paris Agreement by the world’s most powerful economies bar the United States.

Although the G20 summit has further isolated the US, optimists will focus on the continuation of the US renewable energy transition and emissions reduction and a continued commitment by states, cities, companies and citizens despite the best efforts of the current administration.

In a recent interview, former President of Ireland Mary Robinson – a signatory of the letter in Nature – struck a positive note in relation to the US stance: “What President Trump has done is put climate on the American agenda in a way that it was never there before, and provoked a dynamic response from communities, business, civil society, philanthropy.”

A version of this article appeared in the Green News on July 10th, 2017.

New project launched to study links between flooding and waterborne disease outbreaks

A new research project investigating the links between flooding events and the incidence of waterborne infectious disease outbreaks in Ireland was officially launched at UCD Earth Institute today.

The multidisciplinary project will involve social scientists, environmental scientists, engineers and public health researchers from UCD, University of Limerick, DIT and Trinity College.

Flood damage to infrastructure receives widespread media attention but the potential public health consequences for society from future increased flooding as a result of climate change has received little consideration.

A major public health concern, according to Dr Eoin O’Neill from UCD Earth Institute and principal investigator of the project, is that more intense or prolonged rainfall events can mobilise viral and bacterial pathogens from agricultural and domestic sources, transmit them to rivers and groundwater and increase the incidence of waterborne infectious diseases.

Previous research conducted by Dr. Jean O’Dwyer, a UL-based collaborator on the project, has already shown that increased rainfall in Ireland increases the likelihood of groundwater contamination with the familiar pathogen E. coli. 

The project aims to quantify the effects of intensive rainfall and flooding on the incidence and severity of pathogens and to identify the knowledge and awareness gaps of well owners and users in relation to drinking water sources and flood awareness and preparedness.

It is hoped that this project will help reduce the occurrence of illnesses caused by waterborne diseases, such as gastrointestinal illness.

The project will provide an evidence base to inform policy and practice and develop guidelines to inform public authorities when responding to extreme weather conditions.

According to Dr Paul Hynds – an epidemiologist based in DIT and a collaborator on the project: “This should be of particular interest to Irish policymakers including the Environmental Protection Agency (EPA) and Office of Public Works (OPW) as 800,000 Irish people rely on a private unregulated groundwater source (wells) for daily water consumption, in addition to many holidaymakers.”

The project is funded by the Geological Survey of Ireland and the Irish Research Council.

A version of this article appeared in the Green News on July 28th, 2017.

Retailers face higher costs without HFC phase-out, says Environmental Investigation Agency

European retailers face severe financial repercussions if they do not transition to hydrofluorocarbon (HFC)-free cooling technology, the Environmental Investigation Agency warned today.

The EU F-Gas Regulation, brought into law in 2015, legislates for the rapid, stepped phasing out of the use HFCs, which are potent greenhouse gases.

From 2018 HFC supplies will be slashed by 48 per cent. This will make HFC technology far less attractive from a cost point of view and suppliers will be forced to increases prices sharply.

Prices already increased 62 per cent in the first quarter of 2017. The EIA is urging supermarkets and other retailers to speed up the transition.

Clare Perry, head of the EIA’s Climate Campaign, also warned that HFC shortages could drive illegal trade in HFCs in the EU. This black market trade is also a concern in the US.

In their latest Chilling Facts report, the EIA outlined the current retailers that are leading the transition, with Aldi Süd and Tesco topping the list.

Ms Perry said that while European retailers stand out as global leaders in the adoption of HFC-free commercial refrigeration “the uptake across Europe is much short of the pace needed”.

The report highlights that all new Aldi stores in Ireland will use HFC-free refrigeration. Tesco currently has 11 stores in Ireland that use CO2 instead of HFC as a coolant, the report states.

However, Musgraves – a leading grocery and wholesale supplier in Ireland – is lagging far behind and according to the EIA report relies heavily on HFC technology.

HFC use has soared since first introduced as a replacement for banned chlorofluorcarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).

These chlorinated organic compounds were largely responsible for the global atmospheric ozone depletion and were banned as part of the Montreal Protocol in 1987.

Montreal was a landmark agreement and put the ozone layer on a path to complete recovery by the middle of this century. This recovery will prevent harmful cancer-causing UV radiation from reaching the Earth’s surface.

While HFCs are far less damaging to ozone and have a much lower global warming potential (GWP) than CFCs, they still have a GWP thousands of times greater than CO2. In recognition of the dangers of HFCs, a global agreement was reached last year to amend the Montreal Protocol to include the phasing out of HFCs.

A version of this article appeared in the Green News on June 15th, 2017.

Trump’s climate decision dangerous for the US and the world

President Trump tweeted late on Wednesday evening that be will be announcing his decision on whether or not the US will withdraw from the Paris Climate Agreement today at 8PM Irish time.

Unfortunately, and as expected, he announced his decision to withdraw the US from the Agreement which aims to limit global average temperature to within 2°C above pre-industrial levels and combat the unavoidable impacts on people and the Earth.

Under Obama, the US had committed to reducing carbon emissions by 26-28 per cent by 2025.  Now, the US will join only 2 other countries – Nicaragua and Syria – as non-participants in the global deal.

So from a procedural point of view how will the US’s withdrawal proceed? And more importantly, what are the most likely consequences for the US and the world?

Two withdrawal options

Article 28 of the Agreement allows countries to withdraw from the third year after the Agreement entered into force, which would be November 2019 for the US. The withdrawal would also not take effect for another year. So the earliest the US withdrawal would be effective is November 2020.

The other scenario is that the US withdraws from the 1992 United Nations Framework Convention on Climate Change, which necessarily means withdrawing from the Paris Agreement. This could be effective in one year.

Consequences of US withdrawal

One of the worse possible consequences of the US withdrawal from the Paris Agreement is that it could discourage other nations from taking further steps to limit their own emissions, thereby hindering efforts to reduce global emissions. The US withdrawal could also cause diplomatic strain and damage relationships with other countries.

Todd Stern, former US special envoy on climate change under Obama, puts it bluntly in a recent article in the Atlantic stating that “the President’s exit from Paris would be read as a kind of ‘drop dead’ to the rest of the world”.

Withdrawal could also result in the US being left behind in the low-carbon energy transformation. This transition is already underway and China and Europe would likely take primary roles.

China currently accounts for almost 50% of the world’s new solar energy capacity and the US risks falling behind and losing valuable US jobs in the wind and solar energy sectors. The economic importance of committing to the Paris Agreement is recognised by many US industries and companies.

Sixty-nine of 500 US Fortune 500 companies, including Walmart, ExxonMobil, and Chevron, have stated their support for the Paris Agreement. Over 1000 US companies have signed the Business Backs Low-Carbon USA statement urging the US to stay in the Agreement.  Elon Musk, CEO of Tesla, has said he will withdraw for White House advisory councils if President Trumps withdraws.

In an interview in Business Insider UK John Sterman, professor at MIT Sloan School of Management and senior advisor at Climate Interactive said that it is “not far-fetched to imagine a scenario where China…implements a carbon tax on all goods exported from the US”.

Further down the road, the US government could also leave itself open to expensive lawsuits taken by victims of climate change, on the basis that the US withdrawal from the Paris Agreement causes damage and requires compensation.

Carry on Regardless

Many US States and the some of the largest US cities will continue to tackle climate change and transform their energy portfolio regardless of what President Trump decides.

In December 2016, I attended the American Geophysical Union Fall Meeting in San Francisco – the largest meeting on Earth and space sciences in the world. The Governor of California, Jerry Brown, gave a keynote speech and in it he responded to Trumps threat to stop satellite collection of climate data by saying “California will launch its own damn satellites”.

Many US states have invested heavily in clean energy technologies and are proceeding with their energy transformation. Wind and solar energy made up two-thirds of new electric energy capacity in the US last year.

Twelve US cities, representing 25 per cent of the US population, are part of the global C40 Climate Leadership Group.

Will the pressure change Trump’s mind?

With pressure piling from global leaders, environmental charities, scientists, Big Business, Democrats, Republicans and even family members, will Trump rethink his decision to enact one of his pre-election promises?

Ultimately, whether the US are in or out of the Paris Agreement, the new US administration will likely continue making damaging changes to US science, environmental and natural heritage policy.

A version of this article appeared in the Green News on June 1st 2017.

Scientists warn increasing ocean temperatures could destroy world’s coral reefs within decades

New research published in the journal PeerJ, reports that strict conservation and protection measures has failed to halt the destruction of coral reefs in the Hawaiin Islands, with 90% of Hawaiian coral reefs suffering bleaching in 2014 and 2015.

Widespread bleaching of coral reefs, whereby corals expel crucial algae living symbiotically within their tissues, is a stress response to increasing ocean temperatures resulting from global climate change.

Coral reefs are the most diverse marine ecosystems on Earth and provide ecosystem services for millions of people.

Australia’s Great Barrier Reef is also reported to be in “terminal condition” as back-to-back coral bleaching along its 2250-kilometre length in 2016 and 2017 has impacted 70% of the Reef.

Many corals need years to recover and increasing ocean temperatures and back-to-back bleaching events could spell the end for coral reefs within decades. The International Society for Reef Studies predicts that 90% of coral reefs will be at risk of destruction by 2050.

In a recent interview with the Guardian Dr Kim Cobb, a climate scientist at Georgia Tech, said: “the idea that we will sustain reefs in the US 100 years from now is pure imagination. At the current rate, it will be 20 or 30 years, it’s just a question of time”.

This view is mirrored in an article published today in the journal Nature in which Professor Terry Hughes, of the James Cook University in Australia, states that “returning reefs to past configurations is no longer an option”.

The article highlights the need for maintaining and preserving what we have through “radical changes in the science, management and governance of coral reefs”.

A version of this article appeared in the Green News on 2nd June 2017.