Author Archives: Ilissa Ocko

Climate Change and Millennials – An Entire Lifetime of Warmer Than Average Temperatures

While reading the announcement that 2015 had broken – indeed, shattered – the hottest year on record set by 2014, there was one fact that really made things personal: we have now had 31 straight years since a single month was cooler than the twentieth century global average temperature. That means that I have never lived through a month that wasn’t warmer than average – never once in my lifetime.

My entire career as a climate scientist is focused on reducing the threat of global warming, and yet I have never even been alive at a time when the climate was stable. I technically don’t even know what normal is.

Warmest Years on Record graphic

So on one hand, you could say that I don’t even know what I am fighting for. On the other hand, I’ve been afforded two unique opportunities because I’ve lived in the shadow of global warming my entire life.

First, because I’ve grown up at a time when heat records are broken over and over again, I was aware of this worldwide crisis during those impressionable and important “pick a major” years of college. I was thus able to set myself on a career path shaped by climate change from the get-go, rather than later on in life once I was already an established professional in something else.

Second, because my elder colleagues have already identified – with extreme confidence – that humans are the main cause of climate change, I’ve been able to focus on solutions from the get-go, and not just causes and impacts. I have thus benefitted from previous scientific research because I could explore avenues to address climate change, because if humans are the cause, then we are also the solution.

And it’s not just me; there is now an entire generation of young people motivated and empowered to do something about climate change. We – almost the entire millennial generation – have never lived in a world without global warming.

Perhaps for similar reasons to mine (and/or because we think we’re special), my generation has shown a propensity for not just caring about climate change, but doing something about it. Whether on their campuses of their schools or the communities where they live, my generation is showing that they want solutions. In fact, eighty-percent of millennials support cleaner energy in the U.S., regardless of party affiliation.

For this reason among others, I am more hopeful about our future than ever before. Climate change has been impacting my generation our whole lives, but it doesn’t have to stay that way. We didn’t ask for this challenge, but I truly believe we’ll be able to rise up to meet it.

Posted in Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, News, Science| Read 1 Response

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.

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

Just Two Actions May Stop the Planet's Runaway Warming

I was 15 and I was trying to impress a boyfriend with my rollerblading skills — from the top of a steep hill. Before I knew it, I was flying uncontrollably toward traffic. I knew I needed to both slow down and change course . . . or things wouldn't end well.

I did, and I survived, but I've recently thought about that day and those actions as I have considered the urgency needed for the planet to slow down and change course as the climate warms. With two major actions, we can slow the rate of global warming while also preventing "runaway" warming: nations must reduce emissions of both short-lived and long-lived pollutants.

All emissions are not equal

The way people talk and think about the long and short-term impacts of various greenhouse gasses is critical for making smart policy decisions that can effectively slow how fast the climate changes while limiting warming in the future.

While the maximum extent of warming relies on carbon dioxide (CO2) emissions because they last for centuries in the atmosphere, the rate of climate change is controlled by short-lived climate pollutants, such as methane.

Like carbon dioxide, methane is a gas that warms the Earth by trapping heat. Pound for pound, methane is more than 100 times more powerful than CO2 because methane is much more efficient at absorbing heat. But that number changes depending on how far out you look.

Comparing emissions of gases with vastly different radiative impacts and atmospheric lifetimes requires a metric that depends on what timeframe you care about, such as the next decade or next century. One way scientists deal with the temporal differences is by measuring the global warming potential of gases over two time periods: 20 years and 100 years.

Methane is 84 times more effective at trapping heat than CO2 over the first 20 years after they are both emitted, and 28 times more effective over 100 years, because most of the methane breaks down in the first 50 years after it is released due to oxidizing chemical reactions. When discussing what actions to take to reduce methane we must think about methane's potency in both timeframes.

Our best chance of combating climate change

Since the Industrial Revolution, methane in the atmosphere has increased by a whopping 150 percent. While in the same period, CO2 levels have gone up 40 percent. Around one quarter of today's human-caused warming is attributable to emissions of methane, while human-caused CO2 emissions account for around half.

The administration of U.S. President Barack Obama is currently undertaking efforts to reduce emissions of some of the most damaging greenhouse gas emissions  responsible for climate change: methane pollution from oil and gas operations and carbon dioxide from coal-fired power plants. This strategy has prompted questions about which climate pollutant should take priority. But the discussion of whether to cut methane emissions first and carbon dioxide later — or vice versa — is not helpful or necessary. We need a two-pronged strategy to stay safe.

Understanding the urgent need to reduce all types of climate pollution, the Obama administration is expected to move forward with rules to mitigate both methane and carbon dioxide in the next few months. This summer the U.S. Environmental Protection Agency (EPA) is expected to propose the first ever direct regulation of methane emissions from new and modified sources in the oil and gas industry, and finalize its Clean Power Plan to reduce carbon dioxide from coal-fired power plants.

Another agency, the U.S. Bureau of Land Management, is also expected to soon propose important rules to reduce wasteful venting, flaring and leaking of methane associated with the production of oil and natural gas on public lands.

Nations cannot solve the climate crisis and prevent serious impacts without simultaneously reducing both short-lived and long-lived climate pollutants. Reducing CO2 will limit the overall warming the planet will experience generations from now, which will have profound impacts on limiting sea level rise and other dangerous consequences.

Reducing warming caused by methane during our lifetime will also reduce the likelihood of extreme weather events and species extinctions — and, a slower rate also provides more time for societies and ecosystems to adapt to changes.

This post originally appeared on LiveScience.

Posted in Clean Power Plan, Energy, Greenhouse Gas Emissions, Science| Comments are closed

On El Niño, snowballs and real climate science

Source: NASA

Just as we thought science was finally taking root, here comes another article claiming that the rise in global temperatures has nearly stopped over the last 15 years. We heard it most recently from the Wall Street Journal.

Never mind that it’s been 30 years since a month was below the 20th century global average surface temperature. Or that climate change is evidenced by clearly visible sea ice and glacial melt. Skeptics support their argument by pointing out, time and time again, how little the Earth has warmed since 1998.

Indeed, the “nearly-stopped warming” may at face value appear to be supported by convincing scientific data. But don’t be fooled: 1998 was an exceptionally warm year thanks to a very intense El Niño, a naturally-occurring phenomenon involving unusually warm water in the Eastern Pacific Ocean.

The change in temperature from 1998 to today, therefore, is not at all a good representation of the long-term trend. It makes the nearly-stopped warming argument no more scientific than a snowball would be in Washington in February.

Selective statistics don't make a trend

Think of it as if you were to use the holiday season as a benchmark for measuring body weight.

If I looked at the weight change I had between Thanksgiving and December 31, a time of year when I usually enjoy lots of good food, the picture would look very different than if my weight monitoring began the week before Thanksgiving. That's because a Thanksgiving start date would be a higher-than-normal weight day, an anomaly.

And, yet, this is exactly what proponents of the nearly-stopped-warming theory are doing.

While it's true that the rate of temperature change has decreased since 2001, they cherry-pick a recent 15-year period, 1998 to 2012, starting with an initial year that is already way above average to prove their point. Of course, these quasi-scientists aren’t transparent about their strategy, so a non-expert would have to dig into the data to realize they are being tricked.

El Niño always a wild card

El Niño, meanwhile, was just doing what niños tend to do: It threw us for a loop.

The one occurring for 10 consecutive months 1997-98 was the most intense ever recorded, making 1998 the hottest year up until that point. (Three years have since broken that record: 2005, 2010 and 2014.)

Scientists have a number of technical and statistical methods for delineating natural from human influences on the temperature record, and apply these tools depending on the research questions they're trying to answer.

But the overall global record is not touched, so if you don't know which years were affected by natural events such volcanic eruptions, it can look noisy and confusing.

This is why we need to look at long-term trends to get the real answers.

This post originally appeared on our EDF Voices blog.

Posted in Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, Setting the Facts Straight| Comments are closed

Climate hope amid melting ice, rising temps

(This post originally appeared on EDF Voices)

An ice berg drifts off a West Antarctica glacier — Courtesy NASA


As 2014 draws to a close, two recent developments show that global temperatures are rising at an alarming rate. The world, it seems, is on a run-away train – and yet, we have more reason to feel hopeful than we did a year ago.

I’ll explain why that is. But first, let’s have a look at where we are right now.

West Antarctica ice sheet loss is accelerating

The latest science shows that ice loss from West Antarctica has been increasing nearly three times faster in the past decade than during the previous one – and much quicker than scientists predicted.

This unprecedented ice loss is found to be occurring because warm ocean water is rising from below and melting the base of the glaciers, dumping huge volumes of additional water – the equivalent of a Mount Everest every two years – into the ocean.

If we lost the entire West Antarctic ice sheet, global sea level would rise 11 feet, threatening nearly 13 million people worldwide and affecting more than $2 trillion worth of property.

2014 may be warmest year on record

The World Meteorological Organization announced recently that 2014 is on track to be one of the hottest – if not the hottest – year on record.

Continued emissions of heat-trapping gases from energy use, land use, industry, and waste activities contribute to these rising global temperatures.

But there's hope

At Environmental Defense Fund, we spent a year talking to experts from academia, industry, and the activist community to understand what needs and can be done to address climate change.

We analyzed the scientific, economic and political landscapes, and we see that it's possible to reverse the relentless rise of global greenhouse gas emissions within the next five years. But only if countries devote sufficient attention to the task.

What may surprise you is that this can be done with current technology, and at a reasonable cost.

There are two critical components of such a strategy.

One: A few countries can make big progress.

China, the United States, and Europe account for more than half of all global emissions of carbon dioxide from energy use.

Improving energy efficiency, employing carbon markets, enacting power plant standards, and accelerating clean energy deployment are all part of our five-year strategy to curb emissions.

The European Union already has an emission reduction plan in place, the U.S. is taking action on carbon pollution from cars and power plants, and China recently reached a historic agreement with the United States to limit emissions.

Two: By reducing short-lived climate pollutants we'll come a long way.

If we cut emissions of short-lived pollutants such as methane, which only last in the atmosphere for at most a couple of decades, we can take a sizeable bite out of warming in the near-term.

Methane contributes to around a quarter of the warming we are experiencing today, so this is an enormous opportunity we cannot pass up.

We already have the technology in hand to reduce methane emissions from the oil and gas industry in a cost-effective way. Industry would spend just a penny more for each thousand cubic feet of gas it produces.

It’s not too late

While turning the corner on global emissions by 2020 is feasible, it can only happen with many partners working together.

EDF expects to take actions in alliance with many others that contribute to about half of the needed reductions in short-lived and long-lived emissions we've identified in our five-year strategy. We're also working to set the stage for actions post-2020 that will drive down emissions even further.

While some of the climate change consequences may be irreversible – as appears to be the case with West Antarctica – we can still set ourselves on a much better path for the future by taking action now.

Posted in Arctic & Antarctic, Greenhouse Gas Emissions, News, Science| Read 1 Response

An Urgent Call to Climate Action in the IPCC Synthesis Report

Photo: IPCC

It was released two days late for Halloween, but an international report on the dangers of climate change still has plenty of information about our warming planet that will chill you to the core.

The report is the latest from the Intergovernmental Panel on Climate Change (IPCC).

The IPCC releases a series of reports every six or seven years that assess the latest data and research on climate change. This latest is the Fifth Assessment Synthesis Report—a culmination of three earlier reports in this series.

The Synthesis Report summarizes the physical science of climate change; current and future impacts, vulnerabilities, and adaptation of the human and natural worlds; and mitigation opportunities and necessities.

More than anything else, the report underscores the urgent need for action.

Here are 13 details from the report that illustrate why:

1.  “Warming of the climate is unequivocal… The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.”

2.  Changes in climate have impacted all continents and the oceans.

3. The period from 1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere.
Glaciers have continued to shrink almost worldwide. Northern Hemisphere spring snow cover has continued to decrease.

4. Permafrost temperatures have increased in most regions since the early 1980s. Arctic sea-ice has decreased in every season and in every successive decade since 1979.

5. From 1901 to 2010, global mean sea level rose by more than half a foot. The rate of sea-level rise since the mid-19th century has been larger than the mean rate during the previous two millennia.

6. In the future, it is virtually certain that there will be more frequent hot and fewer cold temperature extremes in most areas, on both daily and seasonal timescales. It is very likely that heat waves will occur more often and last longer. The oceans will continue to warm and acidify, and global mean sea level to rise.

7. A large fraction of species face increased extinction risk due to climate change during and beyond the 21st century. Most plant species cannot naturally shift their geographical ranges sufficiently fast to keep up with climate change.

8. Climate change puts humanity at risk from heat stress, storms and extreme precipitation, inland and coastal flooding, landslides, air pollution, drought, water scarcity, sea-level rise, and storm surges. Climate change is projected to undermine food security.

9. “Human influence on the climate system is clear.” Atmospheric concentrations of carbon dioxide, methane and nitrous oxide are unprecedented in at least the last 800,000 years.

10. Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.

11. It is virtually certain that global mean sea-level rise will continue for many centuries beyond 2100, with the amount of rise dependent on future emissions.

12. Many adaptation and mitigation options can help address climate change, but no single option is sufficient by itself. Adaptation can reduce the risks of climate change impacts, but there are limits to its effectiveness.

13. Substantial emissions reductions of greenhouse gases – including carbon dioxide and methane — over the next few decades can reduce climate risks in the 21st century and beyond, increase prospects for effective adaptation, reduce the costs and challenges of mitigation in the longer term, and contribute to climate-resilient pathways for sustainable development.

According to the IPCC Synthesis Report, planet Earth is in pretty dire shape – but the report isn’t hopeless.

Imagine our planet as a patient at a doctor’s office. It’s too late to just stay healthy – we’ve already caught a cold. But we can prevent the cold from deteriorating into pneumonia.

In order to do that, though, we need to act now. We need people, and governments, across the world to join together to reduce greenhouse gas emissions, support adaptation efforts, and help reduce the damages from climate change.

Posted in Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, International, News, Policy, Science| Read 1 Response
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