There are many ways in which we as individuals can impact biodiversity and ecosystem health. One simple positive change would be for households to change their monoculture grass lawns into biodiverse meadows. 

In Sweden, 52% of the urban green areas are lawns and in the United States lawns cover about 2% of the land area. Lawns may cover as much as 1.4% of the global grassland area and lawn grass is the largest irrigated nonfood crop. This is a extremely wasteful use of resources simply to maintain lawnscapes that does not promote biodiversity or food production.

Humanity's population explosion and massive overconsumption of natural resources is killing off wildlife at an unprecedented rate. In the 2018 Living Planet Report by the World Wildlife Foundation (WWF) we come to understand that there has been a 60% decline in species population sizes since 1970. Especially hard hit are the tropics in South and Central America, which have seen a 89% loss compared to 1970. And freshwater ecosystems, like rivers and lakes, have experienced the largest decline of 83%. We have killed off 83% of all mammals and 50% of all plants since the dawn of civilisation, and its irreversible on human timescales. It is truly a biological annihilation as coined in a scientific study published by Ceballos et al. in PNAS last year.

In 2017 the world lost an amount of forest area equivalent to the size of Italy, destroying habitats, causing biodiversity loss and polluting the environment. There is a growing number of scientists that are now calling for a global deal for nature, creating vast nature reserves to prevent biological armageddon.

While climate change is a major threat to all species on Earth a new report published in Nature shows that overexploitation and agriculture are the two biggest culprits of biodiversity loss.

75% of all the plant, amphibian, reptile, bird and mammal species that have gone extinct since 1500s were caused by humans. A growing global population will only put other species under more pressure, and eventually impact human mortality too.

Biodiversity underpins all ecosystem services (e.g. climate regulation, flood protection, pollination, nutrient cycling, water purification etc) that we currently consume "for free" but will have to replace with costly infrastructure or restoration project once they are gone.

Now that we are reaching limits to what these ecosystems are able to withstand without collapsing or drastically altering states we will see a steep increase in costs for the most basic of resources. Those costs are often dumped on the public by the private sector and may not turn up in prices of goods but instead in  form of increasing taxes, poorer health, growing debts etc.

It is truly a sad fact that most people are so disconnected from the land and oceans that they are blind to the fact that Earth's resources are finite. Once a fish stock has collapsed it may never recover, on a timescale relevant to us.

There is no "replay" button that we can magically push and turn back to some previous healthy state. All we can do now is to minimize the damage. And the best way to do that is by not having more kids than we can feed and not consuming more than we actually need for basic needs.

Satellite image of the Great Barrier Reef. Photo Credit: NASA | Wikimedia Commons

The Great Barrier Reef stretches 2,300 km down the eastern coast of Australia. Covering an area the size of Italy it is the largest coral reef on the planet. With over 1500 species of fish, 600 coral species and 30 different whale and dolphin species, it is one of the most biodiverse and complex ecosystems on the planet.

Two weeks ago I wrote about the mass bleaching event that had struck the Great Barrier Reef due to extra warm ocean waters. Now the aerial and underwater survey results are in and it makes for some very sad reading. Only 7% of the reef remains unaffected, in other words, 93% of the reef has suffered damage from the bleaching event. 

“We’ve never seen anything like this scale of bleaching before. In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once,” says Professor Terry Hughes, convenor of the National Coral Bleaching Taskforce

Map of the Great Barrier Reef showing results of aerial surveys for 911 reefs.

“North of Port Douglas, we’re already measuring an average of close to 50% mortality of bleached corals. At some reefs, the final death toll is likely to exceed 90%. When bleaching is this severe it affects almost all coral species, including old, slow-growing corals that once lost will take decades or longer to return.”

I have been away from blogging for a while but decided to try and pick it back up today. So much has happened this spring that I haven't been able to write about so I decided to pick out some key trends/headlines that I found most important.

Source: Coral Reef Watch, NOAA

For a decade now it has been widely debated whether humanity has set in motion a sixth great mass extinction event, comparable to the catastrophe which erased the dinosaurs some 66 million years ago. According to a recent study by Ehrlich et al. (2015) there is no longer any doubt, we truly have.

There is general agreement among biologists that extinction rates have reached levels unparallelled since previous mass extinctions on Earth. However, some have believed the numbers to be overestimated. But this new study confirms that species are disappearing up to about 100 times faster than the normal rate between mass extinctions, known as the background rate. If allowed to continue, life would need millions of years to recover.

The study took a precautionary approach and only allowed for conservative estimates, which means that their calculation probably underestimate the severity of the extinction crisis.

As human population continues to grow and consumers become more affluent more and more natural habitats will be altered or destroyed. Already in 2005 scientists warned that about 60% of all ecosystem services had been degraded or destroyed (Millennium Ecosystem Assessmentt). The long list of impacts include: land clearing for farming, logging and settlement, invasive species, carbon emissions that drive climate change and ocean acidification and toxins that alter and poison ecosystems. 

While there is still much discussion about the causes of some mass extinctions, it is generally believed that they can occur when the biosphere is under long-term stress, for example from a warming climate generated by greenhouse gasses in the atmosphere. As ever more species face extinction we lose the vital ecosystem services they provide, such as: pollination, water purification, pest control, storm control, soil regeneration etc. For its continued existence mankind is reliant upon an untold number of species that maintains the function of those services. As these species disappear, that existence becomes increasingly fragile.

Stanford biologist Paul Ehrlich calls for fast action to conserve threatened species and habitat before the window of opportunity closes. Below is a video from Standford with Ehrlich describing the issue.

Rising temperatures in the Arctic are contributing to melting sea ice, thawing permafrost, and destabilization of a system also known as “Earth’s Air Conditioner”. The Arctic regulates ocean and atmospheric circulation and keeps the the planet cool. Climate change is impacting weather patterns, natural systems, and human life around the world. The Arctic, however, is central to these impacts as it is warming more rapidly relative to lower latitudes, about twice as fast as the rest of the globe, making it “the canary in the coal mine”. What happens in the Arctic is of utmost importance to us humans if we want to know how climate change will impact our only home, planet Earth.

The Arctic is very sensitive to global heat forcing, and any small warming there could rapidly trigger a number of feedbacks that generate more warming for the Arctic and the globe. These feedbacks include but are not limited to: A) snow and ice melting; B) changes in ocean and atmospheric circulation; C) thawing permafrost and methane release. The concept of a “tipping point” - a threshold beyond which a system shifts to an alternate state - has become familiar to most people concerned with the climate debate. If tipping point means crossing a critical threshold in which a system enters substantial, potentially irreversible, change that causes it to move into an entirely new state, there may be precursors or early warning signals of such change. Such warnings are exactly what climate researchers and ecologists are looking for and trying to map out. The graphic below shows potential tipping elements in the Arctic region.

Map show potential tipping points in the Arctic region: ice melting (white); ocean and atmospheric circulation (aqua green); and biome changes (dark green). Source: Lenton (2012)

Snow & Ice melt

Source: meltfactor.org

As snow and sea ice retreat, exposing land and sea with lower albedo (i.e. less reflectiveness), more solar energy is absorbed, thus leading to further melting and retreat in a vicious cycle. The present thinning and retreat of Arctic sea ice is one of the most serious geophysical consequences of global warming and the rate of ice melting have greatly exceeded the predictions of most models (Wadhams, 2012). Experts suggest that we may have, in 2007, passed a tipping point towards having sea-ice free summers in the Arctic (Livina and Lenton, 2013). Some studies suggest that the Arctic could have sea-ice free summers in only a couple of years, 2016-2020 (Maslowski et al. 2012; Wadhams 2014) while others predict it to occur later, around 2041-2050 (Cawley 2014; Liu et al. 2012) given continued warming. Eighty-one percent of Greenland, which is located mostly inside the Arctic Circle and is the world’s largest island, is covered by ice. The Greenland ice sheet is currently losing mass at a rate that has been accelerating (Lenton, 2012). And in July of 2012 Greenland ice sheet reflectivity at 2000m-2500m collapsed during the summer (figure 1). In a study published in Nature Reyes et al. (2014) argued that between 4.5 and 6.0 meters of sea level rise 400,000 years ago could be attributed to a collapse of Greenland's southern ice sheet. Data from marine records in the North Atlantic show that the average temperatures in Greenland during that period were only about 1°C warmer than today’s temperatures. The similarity in climate between then and now “suggests the threshold for ice sheet collapse is pretty low”, according to one of the co-authors, “We could be nearing the tipping point” (Oregon Live, 25th June 2014).

Changes in ocean and atmospheric circulation

Permafrost—the ground that stays frozen for two or more consecutive years—is a ticking time bomb of climate change. Some 24 percent of Northern Hemisphere land is permafrost. That's 23 million square kilometers found mostly in Siberia, the Tibetan Plateau, Alaska, the Canadian Arctic, and other higher mountain regions. When the Arctic warms, permafrost can start thawing and releasing carbon and methane into the atmosphere (figure 2). In a controversial paper in Nature, Comment, Whiteman et a. (2013) posited a scenario whereby a 50 Gigatonne (Gt) methane pulse would occur over a decade time period and calculated its potential economic costs. To put this in context, the total amount of methane in the world’s air now is about 5 Gt, and the annual input is about 0.5 Gt, so this would double the methane in the air within the first year. Newspapers such as the Guardian and popular blogs were quick to pick up the story and claimed that there was a possibility of an Arctic “methane bomb”. Following articles have, however, shown little evidence pointing to the likelihood of such a scenario. A group of international scientists wrote in Nature Geoscience in 2014 that “significant quantities of methane are escaping the East Siberian Shelf as a result of the degradation of submarine permafrost over thousands of years” (Shakova et al. 2014). The authors claim that a sudden release of methane, in a “pulse”, seems unlikely and that methane will probably continue to bubble up slowly, contributing to greenhouse gases in the atmosphere. But they do caution that its possible that global warming could cause more storms in the Arctic Ocean, releasing methane on a bigger scale. There is no established tipping point for methane release, but some studies suggest that a tipping point for continuous Siberian permafrost thaw could be as low as 1.5°C warmer than the pre-industrial period (Oxford University). 

Sea levels are rising due to thermal expansion from warmer oceans and melting of land-based ice. Satellite measures since 1993 show global sea level rise of around 3.2 mm/year (CSIRO). The potential for increases in sea level rise is enormous because the ice caps of Greenland and Antarctic contain over 99% of all the freshwater on Earth (NSIDC). Estimates suggest that if Greenland ice sheets would melt completely it could raise sea level 6 meters. In other words, a one per cent loss of the Greenland ice cap would result in a sea level rise of 6cm (NSIDC). In a process that is accelerating, ice caps are losing mass. In past periods of Earth’s history, levels of atmospheric greenhouse gasses and sea levels have followed one another closely, allowing an inference about where sea level is headed. Sea levels may rise by more than 2 meters for each degree Celsius of warming the planet experiences over the next 2000 years (see figure), according to one study (Levermann et al. 2013). But even a one meter sea level rise could cause major problems for low-lying countries such as the Maldives and Bangladesh, forcing inhabitants to migrate. Around 150 million people live within 1 metre of high tide level (CSIRO). Coastal cities, ports and airports could be flooded, as could cities sited near tidal estuaries, like London. And many nuclear installations are built by the sea which is of great concern knowing what happened in Fukushima.

Shifts in atmospheric circulation could influence weather patterns. Rising temperatures seems to slow down and increase the waviness of the jet stream, increasing long duration extreme weather patterns such as droughts, floods, and heatwaves (YaleEnvironment, 2012). This has significant impacts on temperature and precipitation patterns in Europe and North America. That weather patterns can "get stuck" might explain why the intensity of extreme weather events has increased. We have seen many examples of “stuck” weather patterns during the past few years. Deep southward dips in the jet stream hung over the U.S. east coast and Western Europe during the winters of 2009/2010, 2010/2011, and 2012/2013 bringing a seemingly endless string of snow storms and cold. In the early winter of 2011/2012, in contrast, these same areas were under northern peaks in the jet stream which brought unusually warm and snowless conditions (Francis, 2013). And in summer times persistent weather have been responsible for droughts and heat. The record heat waves in Europe and Russia have been linked to early snowmelt in Siberia (Jaeger and Seneviratne, 2011). These changes affects agriculture, forestry and water supplies. For example, farming becomes more precarious as weather patterns and prognosis are no longer reliable. Changes in weather patterns also impact storm surges and hurricanes. Some scientists suggest that changes to the jet stream drove hurricane Sandy west, towards the coast of northeastern United States (LiveScience, 2013). Ranking as the second costliest hurricane in United States history (Huffington Post, 2013) one can see how changes to storm patterns can have enormous costs to society and the economy.

The complete loss of Arctic summer sea ice has major knock-on effects, such as boosting phytoplankton and absorbing more heat in the oceans. Ocean warming effects marine life in temperate latitudes making species such as cod, haddock and flounder shift their geographic ranges, leaving fewer cold water species (NASA, 2013). Disease also spread faster in warmer water so parasites are having larger effects on species, especially sensitive coral reefs. Because the planet’s oceans currently absorb about a quarter of the carbon dioxide, which lowers the pH level of the water, the oceans are becoming acidic. Acidification makes shell-formation among marine organisms such as plankton and mollusks more difficult, which could have major cascading effects on marine life as these organisms make up the base of the ocean’s food chain. Coral reefs, which are marine biodiversity hotspots, are particularly sensitive to changes in temperatures and pH. Coral reef ecosystems are in global decline and this means loss of storm buffers and loss of estuaries for fish species that generate 200 million jobs and food for a billion people (NOAA).

According to most scientists, a CO2 amount of order 450 ppm or larger, if long maintained, would probably push Earth toward an ice-free state (Hansen et al. 2008, 2013). 450 ppm is considered a climate tipping point, beyond which we would have no control. We are at 400 ppm today, which constitutes high risk of transgressing the tipping point. According to science we need to get back down to 350 ppm to be considered in the safe zone. 

Some studies suggest that we may have passed a tipping point in relation to having sea-ice free summers in the Arctic already in 2007 (Livina and Lenton, 2013). The loss of reflective surfaces in the summer reinforces further warming, as dark water absorbs more heat from the sun, causing further melting. The loss of summer sea-ice cover is reversible, given that warming slows down (i.e. drastic reduction in greenhouse gas emissions). 

By looking at sediment records a team of scientists found that 1°C warmer than today's temperatures in Greenland contributed to a 4-6 meter sea level rise from the collapse of the southern part of the ice sheet (Reyes et al., 2014). 

At 1.5°C warming, from pre-industrial levels, Siberian permafrost starts thawing on a large scale (Vaks et al., 2013). Crossing this tipping point could potentially lead to runaway climate change because of the scale of carbon stores and because methane is 20 times more effective in increasing global temperatures than equal amount carbon dioxide.

What is happening in the Arctic impacts us all. Rapid climate changes are now taking place in the Arctic with impacts on a planetary scale. We do not know how to fix it except from lowering our emissions. Many experts say we need a rapid reduction in greenhouse gas emission, starting now. Global leaders have to come to an agreement that substantially reduces emissions, the rich world taking the lead. Our only home, the Earth, is changing rapidly and we are now running into dangerous risks of substantial warming and triggering climate tipping points that reinforces further warming beyond our control. The last call is coming up in November of 2015 Paris Climate Meeting. “The Arctic acts as an early warning system for the entire planet” (Dr. Chip Miller, NASA Jet Propulsion Laboratory). We should all follow what happens there closely and warn the world of the potential dangers of going on with "business as usual".

“Biodiversity is the totality of all inherited variation in the life forms of Earth, of which we are one species. We study and save it to our great benefit. We ignore and degrade it to our great peril.” — E.O. Wilson

State of global biodiversity

Biological diversity (i.e. biodiversity) reflects the number, variety and variability of living organisms. It includes diversity within species, between species, and among ecosystems. The concept also covers how this diversity changes from one location to another and over time. Indicators such as the number of species in a given area can help in monitoring certain aspects of biodiversity. When one wants to understand the health of an entire ecosystem, however, some species may be more important than others in the sense that they provide a key function within the entire system. Ecologist often refer to such species as keystone species. Take for example the otter. They are considered a keystone species because of their critical importance to the health and stability of nearshore marine ecosystems. Otters eat sea urchins and other invertebrates that graze on giant kelp. Without sea otters, these grazing animals can destroy kelp forests and consequently the wide diversity of animals that depend upon kelp habitat for survival (Fig. 1). Additionally, kelp forests protect coastlines from storm surge and absorb carbon dioxide from the atmosphere.

Aquaculture is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. At the moment aquaculture is the fastest growing food sector in the world. From 1990 to 2010 cultivation of fish and shellfish in terrestrial and marine systems grew at an annual rate of 7.8% worldwide, a much higher rate than any other food commodity. Although there are many potential benefits to farming aquatic organisms such as increases in food and fuel supply there are also many potential drawbacks. In this post I will go through some of the latest scientific findings regarding the pros and cons of aquaculture from a global food security perspective.

Fig.1 Map over societies dependence (%) on fish for nutrition (2008)

Fish is an important food commodity and more than 3 billion people obtain ⅕ of their animal protein from fish. Some societies are more dependent on fish as a source of nutrition than others (Fig. 1). In 2012 the global fish market was valued at 129 billion dollars. However, global wild fish catches peaked around 2002-2003 and is now at a plateau (Fig. 2a and b), thus, there is an sense of urgency in the scientific and public policy community to match the gap in food needed with sustainable options.The international community's interest in aquaculture has thus become ever more present. And business is booming, roughly half of the fish consumed worldwide now comes from aquaculture and its share is expected to increase in the future as wild fisheries exceed their sustainable limits (Troell et al. 2014). Freshwater fish comprise the majority of aquaculture production today. These fish are raised in ponds, lakes, canals, cages and benefit from a wide range of inputs, technology and management.

The most common environmental problems include pollution of marine ecosystems, destruction of coastal habitats, enhanced disease and parasite transmission between farmed and wild fish populations, introduction of invasive species, increased stress on freshwater resources, and overfishing of wild fish stocks to feed farm fish. The use of wild fish in feeds can also have food security implications for low-income households that depend on low-trophic level fish as a key source for nutrition.

Since there are both major benefits and risks to aquaculture one way to make a risk analysis is to use a portfolio approach. The basic idea is to invest in a suite of assets or activities that collectively has lower risk relative to that of any individual asset. This will yield trade-off options between risk and returns and the trick is to diversify the asset bundle. The degree of risk depends on correlations between assets’ returns. When applying this approach to the global food systems one could think of the targeted return as the aggregate output of food commodities needed to meet human demands. Risks, then, involve temporary and irreversible declines in productivity captured by the variation and trend in food production and prices. Furthermore, the degree of food price volatility is indicative of the global food system’s resilience (or robustness) against a wide range of stressors such as pests, extreme weather events, climate variability and other market shocks related to changes in the energy and financial sectors. A pattern of higher and more variable prices over time would then suggest deteriorating resilience of global food supplies whilst a pattern of stable prices would indicate a more robust and resilient food system.

Source: Troell et al. (2014)

Diversify, diversify, diversify

Conclusion

Emerging infectious diseases (EID) may have a lot to do with changing environmental conditions and human-wildlife interaction. EID are either new types of pathogens or old ones that have mutated to become novel, as the flue does every year. Most known human EID are shared with animals meaning they are zoonotic. There is an excellent map over hot spots for EIDs in the world that was published in the New York Times back in 2012 that can be found here. While the research field, ecology-infectious diseases, is relatively new and crosses disciplinary boundaries I believe it should get more attention. Especially since it may tell us more about why EIDs have become so prevalent over the last couple of decades.

Ebola

While Ebola is a really scary disease because of its high fatality rate (50-90 %) its just one of nearly 1,000 known human diseases that have originated from animals. The specific source of the Ebola outbreak is not known, however, Ebola is thought to be naturally harboured in some species of bats. Initial transmission to humans may thus have come about via butchering or consuming bats or other infected species. VICE News made a great short documentary about bushmeat in the time of Ebola. While Ebola has had a devastating impact in west African countries it is unlikely that Ebola becomes a global pandemic since the infection pathway requires direct contact with bodily fluids. That said, the illegal bushmeat trade could potentially act as a transfer of the disease in to other countries around the world. Anyway, the Ebola outbreak serves as a reminder of the linkages between disrupted ecosystems and human illness.

Ecology

The more we humans expand our footprint and population, altering habitats and moving animals (and the pathogens they carry), the greater potential for infection and spread of pathogens novel to humans. For example, overfishing in an area could lead to an increase in bushmeat consumption due to subsistence standards which in turn could increase the prevalence of EIDs. Similarly deforestation forces animals to move into closer proximity to humans leading to closer contact, conflicts and loss of biological diversity. Moreover warming temperatures due to climate change may also change habitats and create new ones suitable for species and their pathogens. Examples range from mosquitoes to fruit bats.

Source: Future Earth

Coordination?

Some international groups such as WHO, Future Earth, Diversitas have come together and created the ecoHEALTH project, bringing together researchers from different fields to investigate connections between health and environmental change to generate policy outputs. Hopefully this crisis may shed some new light on prevention methods that include a better care for the worlds ecosystems and biodiversity. For example; combating illegal wildlife trade, improving sanitation, halting deforestation and securing more eco-friendly food production. At the moment many international help organizations are are instead struggling to keep up with all the emerging health crises. Doctors without borders (MSF) have their work cut out for them, combating both disease outbreaks and humanitarian crises, from outbreaks of MERS, Ebola and the Avian Flue to conflicts in South Sudan, Central African Republic and Syria. The organisations spokesperson begged the UN for more resources to combat the Ebola Outbreak, as many countries have not responded quickly enough to the crisis. One should understand that these are costly ways of trying to handling public health issues, much more can be done and to a lower cost on the side of prevention. We have the tools, now we only need foresight.

Conclusion

The complex dynamics of EID has become a hot topic. Hopefully more countries will start taking into account the overlapping drivers of disease and environmental change. Thinking of human health as separate from animal health and their determinants should be a thing of the past. Understanding the underlying parameters, such as human-wildlife proximity and habitat change, of disease outbreak could help organizations set up global monitoring services and look for early warnings of new outbreaks.