Selected category: Plants & Animals

Six Climate Tipping Points: How Worried Should We Be?

One of the biggest fears about climate change is that it may be triggering events that would dramatically alter Earth as we know it.

Known to scientists as “tipping events,” they could contribute to mass extinction of species, dramatic sea level rise, extensive droughts and the transformation of forests into vast grasslands – among other upheavals our stressed world can ill afford.

Here are the top six climate events scientists worry about today.

1. The Arctic sea ice melts

The melting of the Arctic summer ice is considered to be the single greatest threat, and some scientists think we’ve already passed the tipping point.

As sea ice melts and the Arctic warms, dark ocean water is exposed that absorbs more sunlight, thus reinforcing the warming. The transition to an ice-free Arctic summer can occur rapidly – within decades – and this has geopolitical implications, in addition to a whole ecosystem being disrupted.

Photo: Smudge 900)

2. Greenland becomes ice-free

The warming of the Arctic may also render Greenland largely ice-free. While Greenland’s ice loss will likely reach the point of no return within this century, the full transition will take at least a few hundred years.

The impacts of the Greenland ice melt is expected to raise sea levels by up to 20 feet.

Half of the 10 largest cities in the world, including New York City, and one-third of the world’s 30 largest cities are already threatened by this sea level rise. Today, they are home to nearly 1.8 billion people.

Other vulnerable American cities include Miami, Norfolk and Boston.

Photo: siralbertus

3. The West Antarctic ice sheet disintegrates

On the other side of Earth, the West Antarctic ice sheet is also disintegrating. Because the bottom of this glacier is grounded below sea level, it’s vulnerable to rapid break-up, thinning and retreat as warm ocean waters eat away at the ice.

Scientists expect the West Antarctic ice sheet to “tip” this century, and there is evidence that it already began happening in 2014.

However, the entire collapse of the glacier, which would raise sea level by 16 feet, could take a few hundred years.

Photo: BBC World Service

4. El Niño becomes a more permanent climate fixture

The oceans absorb about 90 percent of the extra heat that is being trapped in the Earth system by greenhouse gases. This could affect the ocean dynamics that control El Niño events.

While there are several theories about what could happen in the future, the most likely consequence of ocean heat uptake is that El Niño, a natural climate phenomenon, could become a more permanent part of our climate system.

That would cause extensive drought conditions in Southeast Asia and elsewhere, while some drought-prone areas such as California would get relief.

The transition is expected to be gradual and take around a century to occur – but it could also be triggered sooner.

Photo: Austin Yoder

 5. The Amazon rain forest dies back

Rainfall in the Amazon is threatened by deforestation, a longer dry season, and rising summer temperatures.

At least half of the Amazon rainforest could turn into savannah and grassland, which – once triggered – could happen over just a few decades. This would make it very difficult for the rainforest to reestablish itself and lead to a considerable loss in biodiversity.

However, the reduction of the Amazon ultimately depends on what happens with El Niño, along with future land-use changes from human activities.

Photo: World Bank

 6. Boreal forests are cut in half

Increased water and heat stress are taking a toll on the large forests in Canada, Russia and other parts of the uppermost Northern Hemisphere. So are forest disease and fires.

This could lead to a 50-percent reduction of the boreal forests, and mean they may never be able to recover. Instead, the forest would gradually transition into open woodlands or grasslands over several decades.

This would have a huge impact on the world’s carbon balance because forests can absorb much more carbon than grasslands do. As the forest diminishes, the climate will be affected as will the Earth’s energy balance.

However, the complex interaction between tree physiology, permafrost and fires makes the situation tricky to understand.

Photo: Gord McKenna

Other concerns…

As if that’s not enough, there are a few other tipping events that scientists are also concerned about, but they are even more complex and harder to predict. Examples of such events include the greening of the Sahara and Sahel, the development of an Arctic ozone hole and a chaotic Indian summer monsoon.

How do we keep from tipping over?

We know from measurements that the Earth has had many climate-related tipping events throughout its history. Today’s situation is different, because humans are now driving these changes and the warming is occurring at a faster rate.

But as humans we also have the power to change the trajectory we’re on – possibly in a matter of a few years. We think we know how.

Also posted in Arctic & Antarctic, Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, Oceans| Read 1 Response

'Feeding 9 billion' requires facing up to climate change

This post was co-authored by Kritee, Senior Scientist, International Climate; Richie Ahuja, Regional Director, Asia; and Tal Lee Anderman, Tom Graff Fellow – India Low-Carbon Rural Development

National Geographic's May cover story, “Feeding 9 billion,” offers valuable insights into how to feed a growing global population while reducing agriculture’s environmental impacts. But it omits some key connections with a critical issue: climate change.

Drought in the U.S. causes withering of corn. (Photo credit: Ben Fertig, IAN, UMCES)

As the Food and Agriculture Organization recently documented in great detail, climate change is likely to fundamentally alter the structure of food systems around the globe. With about 43% of the world’s population employed in agriculture, it’s vital that farmers have the knowledge and tools they need both to adapt to climate change and to help mitigate it.

Author Jonathan Foley, who directs the University of Minnesota’s Institute on the Environment, lays out several steps for “Feeding 9 billion.” Though he starts by acknowledging that agriculture emits “more greenhouse gases than all our cars, trucks, trains, and airplanes combined,” he doesn’t explicitly mention how his plan relates to a changing climate.

The first of his steps – halting conversion of additional forests and grasslands to agriculture – is crucial to stopping climate change, given the vast quantities of greenhouse gases released in these conversions. As the latest Intergovernmental Panel on Climate Change (IPCC) report on mitigation noted, protecting forests and increasing carbon content of the soils can decrease global emissions by as much as 13 gigatons CO2eq/year by 2030 – more than a quarter of current annual global emissions.

Foley also highlights the need to reduce meat consumption, because only a very limited portion of calories consumed by animals yield edible food for humans, and to reduce food waste. According to the IPCC, these consumer-level steps have the potential to decease agricultural emissions by 60% below the current trajectory. While Foley didn’t acknowledge these mitigation potentials, we agree that these are important steps to feeding the world’s population and protecting our environment.

But it’s his steps calling for improving productivity – both by growing more food on existing farms, and by using fertilizer, water and energy more efficiently – where the interactions with climate are more complex and need special attention.

Climate adaptation and resilience in agriculture

Foley rightly points out that to feed the world’s future population, more food needs to grow on existing farms. However, he doesn’t note that some of the effects of climate change – droughts, floods and heat waves in many parts of the world – are already reducing crop yields, and these effects and their consequences are expected to worsen.

The IPCC’s recently published 5th Assessment Report on adaptation concludes that:

  • Climate change is already negatively affecting yields of crops and abundance of fish, and shifting the regions where crops grow and fish live
  • Future changes in climate will increase competitiveness of weeds, making it difficult and more expensive to control them
  • By 2050, changes in temperature and precipitation alone will raise global food prices by as much as 84% above food prices projected without these two climatic factors
  • Major grains like wheat, corn, and rice could see as much as a 40% decrease in yield from a 20C increase in local temperatures. That’s because of the changing rainfall frequency and intensity, unpredictability and irregularity of growing seasons, and higher ozone levels that often accompany high CO­2 levels

To deal with these consequences and ensure food security and livelihoods, adaptation to climate change is essential. Indeed, adopting carefully chosen adaptation and resilience measures could improve crop yields as much as 15-20%. The IPCC recommendations include:

  • Altering planting/harvesting dates to match the shifting growing seasons
  • Using seed varieties that might be more tolerant of changing climatic patterns
  • Better managing water and fertilizer use

A farmer training session, led by EDF’s partner NGO in India (Photo credit: Accion Fraterna)

Achieving high yields requires enabling farmers all over the world to adapt, build and restore the resilience of agricultural ecosystems in the face of continued climate change. Given that many farmers in developed countries have already reached what are currently maximum possible yields, it’s particularly urgent to work with farmers in the developing world.A vast majority of these farmers in developing countries own small-scale farms (less than two acres in size) and have limited resources, and as a result are on the frontline of experiencing the unfolding impacts of climate change. These farmers are already growing the majority of the world’s food – more than 90% of the world’s rice, over 65% of its wheat and 55% of its corn. Notably, as opposed to our recommendations for farmers in the developed countries, some of them might need to increase their fertilizer use to achieve better yields as opposed to decreasing it. Feeding a world of 9 billion thus requires facing the disproportionate effect that climate change has on the 2 billion people who depend on small-scale farms for their livelihood.

Barriers to climate adaptation & mitigation in agriculture

The latest IPCC report also noted that the “nature” of the agriculture sector means:

“There are many barriers to implementation of available mitigation options, including accessibility to … financing, … institutional, ecological, technological development, diffusion and transfer barriers.”

We couldn’t agree more.

Many farmers, especially small scale land-owners in developing parts of the world, lack access to reliable scientific information and technology. In some cases, relevant information has not even been generated.

An Indian peanut farm where EDF is monitoring yield and greenhouse gas emissions. (Photo credit: Richie Ahuja)

For example, small-scale rice farmers in Asia lack access to information enabling them to determine what amounts of water, organic and synthetic fertilizer will optimize yields while also minimizing release of the greenhouse gases methane (which is 84 times more potent than carbon dioxide in the first 20 years after it is released), and nitrous oxide (which is nearly 300 times more potent than carbon dioxide). EDF is working with the Fair Climate Network in India and with Can Tho University and other partners in Vietnam to help generate that information and facilitate its use by farmers.

More generally, agricultural institutions at all levels – international, regional, national and local – need to work closely with farmers to learn and promote evidence-based, locally appropriate agricultural adaptation and mitigation technologies and practices. Farmer access to finance can further help improve the adoption rate of these technologies. Larger investments in farming infrastructure and science from government and private sector also need to be channeled to promote food security through low-carbon farming.

Our food system cannot achieve high yields without building and restoring the resilience of agricultural ecosystems, and the system won’t be sustainable if agriculture doesn’t do its part to mitigate climate change.

To feed 9 billion people, we must overcome barriers to reducing climate change’s effects on agriculture, and agriculture’s effect on climate.

This post first appeared on EDF Talks Global Climate blog

Also posted in International, Policy, Science| Read 2 Responses

7 American Species Threatened by Global Warming

Canada Lynx
The Canada lynx is at risk because of changes to the snowpack caused by climate change.

With the political debate heating up over the American Clean Energy and Security Act, it's easy to lose sight of what the fight is about.

Yes, this is about people and jobs and freeing ourselves from foreign oil and creating a clean energy economy for the 21st century. But it's also about our natural heritage and the wildlife with which we share this planet.

Species from blue whales to butterflies confront growing threats. Their habitats are rapidly changing along with the climate. Global warming is pushing nature to the brink.

That's why we launched a new campaign, Warming and Wildlife, where we document the story through the prism of seven "ambassador species" from across America already struggling to survive.

Without action, there's a good chance these species won't make it — we could lose them in our lifetimes.

Our seven ambassador species are:

The bumper sticker is right: Extinction is forever. But, it doesn't have to be inevitable, not if we each do our part to cap America's global warming pollution and unleash the clean energy economy of the 21st century.

Posted in Plants & Animals| Comments are closed

Old-Growth Forests Still Taking Up Carbon

Lisa Moore's profileOld Growth ForestOld-growth forests hold vast amounts of carbon from centuries of growth, and this carbon would be released into the atmosphere if the trees were cut down. That much has been known for a long time, which is why Environmental Defense Fund so strongly advocates a plan to reduce deforestation in developing countries.

But new research shows that old-growth forests are even more important than previously thought. According to a new study in Nature, old-growth forests aren’t just standing there maintaining the status quo. They still actively take up CO2 from the atmosphere.

Read More »

Also posted in International| Comments are closed

Extinctions Increase with Global Warming

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

Earth is home to millions of species. This rich biodiversity isn't just beautiful, it's also tremendously valuable. As just one example, consider coral reefs. They support fisheries that are the main source of protein for a billion people, and bring billions of tourist dollars into local economies.

Scientists have warned that climate change puts a large fraction of Earth's species at risk for extinction. Most of these predictions are based on comparisons between species' apparent climate requirements to projections of future conditions. A new study [PDF] in the Proceedings of the Royal Society B looks at the relationship between climate and biodiversity from a different perspective: the Earth's deep past. The study found a long-term correlation between global temperature and extinction.

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Posted in Plants & Animals| Read 1 Response

Climate News: Creeping Shrubs and Record Heat

The author of today's post, Lisa Moore, Ph.D., is a scientist in the Climate and Air program.

This week I came across several interesting articles related to climate, but two in particular caught my eye. In the first, scientists found that excess carbon dioxide (CO2) may be what's leaving livestock with less food to eat. The other study explores the role of greenhouse gases on the record-breaking heat Americans experienced in 2006.

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Posted in Plants & Animals| Comments are closed
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