Elevated CO2 Levels Directly Affect Human Cognition, New Harvard Study Shows

ThinkProgress - Joe Romm

In a landmark public health finding, a new study from the Harvard School of Public Health finds that carbon dioxide (CO2) has a direct and negative impact on human cognition and decision-making. These impacts have been observed at CO2 levels that most Americans — and their children — are routinely exposed to today inside classrooms, offices, homes, planes, and cars.
Carbon dioxide levels are inevitably higher indoors than the baseline set by the outdoor air used for ventilation, a baseline that is rising at an accelerating rate thanks to human activity, especially the burning of fossil fuels. So this seminal research has equally great importance for climate policy, providing an entirely new public health impetus for keeping global CO2 levels as low as possible.
In a series of articles, I will examine the implications for public health both today (indoors) as well as in the future (indoors and out) due to rising CO2 levels. This series is the result of a year-long investigation for Climate Progress and my new Oxford University Press book coming out next week, “Climate Change: What Everyone Needs to Know.” This investigative report is built on dozens of studies and literature reviews as well as exclusive interviews with many of the world’s leading experts in public health and indoor air quality, including authors of both studies.

What scientists have discovered about the impact of elevated carbon dioxide levels on the brain
Significantly, the Harvard study confirms the findings of a little-publicized 2012 Lawrence Berkeley National Laboratory (LBNL) study, “Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance.” That study found “statistically significant and meaningful reductions in decision-making performance” in test subjects as CO2 levels rose from a baseline of 600 parts per million (ppm) to 1000 ppm and 2500 ppm.
Both the Harvard and LBNL studies made use of a sophisticated multi-variable assessment of human cognition used by a State University of New York (SUNY) Upstate Medical University team, led by Dr. Usha Satish. Both teams raised indoor CO2 levels while leaving all other factors constant. The findings of each team were published in the peer-reviewed open-access journal Environmental Health Perspectives put out by the National Institute of Environmental Health Sciences, a part of NIH.
The new study, led by Dr. Joe Allen, Director of Harvard’s Healthy Buildings program, and Dr. John Spengler, Professor of Environmental Health and Human Habitation at Harvard, used a lower CO2 baseline than the earlier study. They found that, on average, a typical participant’s cognitive scores dropped 21 percent with a 400 ppm increase in CO2. Here are their astonishing findings for four of the nine cognitive functions scored in a double-blind test of the impact of elevated CO2 levels:

The researchers explain, “The largest effects were seen for Crisis Response, Information Usage, and Strategy, all of which are indicators of higher level cognitive function and decision-making.” The entire article is a must-read as is the LBNL-SUNY study.
NASA has also observed CO2-related health impacts on International Space Station (ISS) astronauts at much lower CO2 levels than expected and has identified a mechanism by which CO2 levels could affect the brain, as I will discuss in Part 2. As a result, NASA has already lowered the maximum allowable CO2 levels on the space station. The ISS crew surgeon who is the lead for studying the impact on astronauts of CO2 (and other gases) told Climate Progress he considers the original LBNL-SUNY study “very credible.” Indeed, NASA itself is now starting terrestrial studies to look at the impact of CO2 on judgment and decision-making for the astronaut cohort — and it is partnering with the same SUNY team of behavioral psychologists.
All of this new research is consistent with — and actually helps explain — literally dozens of studies in the past two decades that find low to moderate levels of CO2 have a negative impact on productivity, learning, and test scores. See here for a research note and bibliography of some 20 studies and review articles.

The impact of fossil fuels and modern buildings on human cognition
For most of human evolution and modern history, CO2 levels in the air were in a fairly narrow and low range of 180 to 280 parts per million. Also, during the vast majority of that time, humans spent most of their time outdoors or in enclosures that were open (like a cave). Even once humans built dwellings, those were not tightly sealed as modern buildings are. So even though we generate and breathe out CO2, homo sapiens were not generally exposed to high, sustained CO2 levels.

But in recent decades, outdoor CO2 levels have risen sharply, to a global average of 400 ppm. Moreover, measured outdoor CO2 levels in major cities from Phoenix to Rome can be many tens of ppm higher — up to 100 ppm or more — than the global average. That’s because CO2 “domes” form over many cities primarily due to CO2 emissions from traffic and local weather conditions.
The outdoor CO2 level is the baseline for indoor levels. In buildings — the places where most people work and live — CO2 concentrations are considerably higher than outdoors. CO2 levels indoors that are 200 ppm to 400 ppm higher than outdoors are commonplace — not surprising since the design standard for CO2 levels in most buildings is 1000 ppm. In addition, that differential increases when more people are crammed into a space and when the ventilation is not adequate. As the Harvard researchers point out, in recent decades, buildings have become more tightly sealed, and there has been less exchange of inside air with fresh outside air.
How high can CO2 levels get indoors? As but one salient example, the 2012 LBNL-SUNY article notes, “In surveys of elementary school classrooms in California and Texas, average CO2 concentrations were above 1,000 ppm, a substantial proportion exceeded 2,000 ppm, and in 21% of Texas classrooms peak CO2 concentration exceeded 3,000 ppm.” In Part 3, I’ll look at the extensive literature on the relationship between high classroom CO2 levels and poor student performance — and the simple strategies Indoor Environmental Quality experts say that parents, teachers, and school administrators should be doing now to address this serious problem.
Yet, the vast majority of studies linking CO2 levels to poorer performance at work and school merely used CO2 as a measure of ventilation rates and indoor air quality (since monitoring CO2 levels is relatively cheap and easy). As the LBNL-SUNY study notes, “It has been widely believed that these associations exist only because the higher indoor CO2 concentrations occur at lower outdoor air ventilation rates and are, therefore, correlated with higher levels of other indoor-generated pollutants that directly cause the adverse effects,” such as volatile organic compounds and particulates.
As a result, “CO2 in the range of concentrations found in buildings (i.e., up to 5,000 ppm, but more typically in the range of 1000 ppm) has been assumed to have no direct effect on occupants’ perceptions, health, or work performance.” In short, CO2 had not been a suspect in the negative impacts measured in all these studies. Indeed one of the authors of the LBNL-SUNY study, Dr. William Fisk, leader of LBNL’s Indoor Environment Group, told me that he was surprised when the testing showed significant impacts from just raising CO2 indoor CO2 levels 400 ppm.
Yet very few of those other studies offered a specific mechanism for the negative impacts they measured beyond hand-waving assertions of “inadequate indoor air quality.” With the recent work from the Harvard, LBNL, SUNY, and NASA researchers, however, we now have at least a partial answer to the mystery, according to several experts I spoke to: High CO2 levels don’t merely serve as an indicator of poor air quality that causes occupants problems, they are actually one cause of those problems.
Interestingly, the authors of all of these studies — the direct CO2 studies and the CO2-as-a-proxy-for-ventilation studies — are generally public health researchers focused on indoor environmental quality (IEQ). As a result, their published work does not examine the implications these findings have for climate policy.

The risks of doing nothing
But the implications for climate policy are stark. We are at 400 parts per million (ppm) of CO2 today outdoors globally — and tens of ppm higher in many major cities. We are rising at a rate of 2+ ppm a year, a rate that is accelerating. Significantly, we do not know the threshold at which CO2 levels begin to measurably impact human cognition.
The LBNL study found a measurable negative impact on human cognition at 1000 ppm. The Harvard researchers had a more comprehensive study that found significant negative impact at 930 ppm. Moreover, many measurements made by the Harvard team point to a much lower threshold, as the top figure shows. Equally important, the researchers found “The exposure-response between CO2 and cognitive function is approximately linear across the concentrations used in this study.” So the impact threshold may be quite below 930 ppm. Clearly more research needs to be done to solve this detective story.
he latest IEQ research does offer strong suggestions that the threshold could be near (or possibly even below) levels the entire world could experience outdoors over the next hundred years — levels that are essentially irreversible for centuries.
As one clue to where that threshold may be, we can turn to recent research from Carnegie Mellon University (CMU) for the U.S. General Services Administration, which found a threshold of about 600 ppm. At 1,282 workstations in 64 diverse buildings across the country, CMU measured CO2 levels and surveyed occupancy perception of air quality.
The result: “An in-depth analysis reveals that occupant satisfaction with overall air quality is strongly linked to CO2 levels, with significant shifts to satisfaction when CO2 is less than 600 ppm.” That’s from an as-yet unpublished CMU thesis “Are Humans Good Sensors? Using Occupants as Sensors for Indoor Environmental Quality Assessment and for Developing Thresholds that Matter,” for a Ph.D. in “Building Performance and Diagnostics.”
I spoke to the chair of the thesis committee, Vivian Loftness — University Professor and former Head of the School of Architecture — one of the world’s leading experts on “Health, Productivity, and the Quality of the Built Environment,” which is a graduate course she teaches. Over the last quarter century, she has assembled the most extensive database in the world of studies on the health and productivity gains from green building design. I first met her when I was working on a book of case studies on that very subject in the late 1990s.
Loftness, who oversaw the GSA study, explained that CMU’s analysis showed that “humans are pretty good sensors of high CO2 levels.” Occupant perception of indoor air quality drops sharply as CO2 levels rise from 600 to 750 ppm.
She is familiar with the recent work showing a direct link between CO2 and human cognition. She said of the original LBNL-SUNY study, “a seminal piece of work and a great research team.” She considers the Harvard study “an absolutely important study.”
Loftness draws two key conclusions from these studies, her own work, and the vast database of scientific literature she has surveyed. First, the immediate public health message is to increase ventilation and the use of outside air in buildings. And second:

We have to do everything we can to keep outdoor CO2 levels below 600 ppm because something serious starts happening then.

Researchers at Climate Interactive put together a chart of where CO2 levels headed as we head into the crucial Paris climate talks in December.

The world had been on a path toward 900 ppm of CO2 in the air by 2100. Commitments made by major countries to cut or constrain CO2 emissions through 2030 — Intended Nationally Determined Contributions (INDCs) — would put us on a sharply lower trajectory. To avoid catastrophic impacts, however, we will need much stronger commitments post-2030.

Success at Paris, as I have written, would buy us 5 to 10 years in the fight to avoid catastrophe. But we would still be on a path to 675 ppm, which is too high for both the climate change impacts and the direct human cognition impacts. Worse, that level of warming will likely trigger many major carbon-cycle amplifying feedbacks that are not included in the climate models, such as permafrost melting. So we must take stronger action.
On the immediate public health front, we need to start monitoring indoor CO2 more closely and keep inside levls as close as possible to levels outdoors through greater use of outside air. According to the building design experts I have interviewed, such as Dr. Loftness, that can be done without increases in building energy consumption using cost-effective strategies and technologies available today. Indeed, systematic green design will lower total energy consumption. I will examine these design strategies later in this series.

Paris Climate Summit: 'The World Is Ready For Change'

The Guardian - Christiana Figueres

Cop 21: UN Climate Change Conference Paris
The political will to act on climate has arrived. We will look back at Paris as a turning point of this century towards a brighter future

National climate plans have been put forward by 156 countries ahead of the Paris summit.
Photograph: Courtesy of IISD

Change is created by turning points. Whether through evolution or revolution, turning points in history have changed the way we think, move, communicate, live.
We are at a turning point now. A decisive hour when a historical event occurs, when a decision must be made, when we have understood that the consequences of the past need us to intentionally and decisively redefine the future.
The latest session of the climate change negotiations took place last week, and while I work in this process to support the governments of the world to adopt a legally-binding climate agreement, we should remember that international negotiations don’t cause change, they mark it. The change has already been happening in the “real economy” through a series of mutually reinforcing and increasingly powerful drivers:
• Science has warned that fossil fuels cannot all be burnt if we are to avoid catastrophic climate change. This is changing how investors and shareholders think about risk and whether they are exposed to values that will become stranded. The divestment movement has grown to $2.6tn as capital shifts towards lower risk opportunities.
• The insurance industry is waking up to the uninsurability of uncontrolled climate change, leading to stark warnings, notably by Mark Carney, chair of the Financial Stability Board, that disclosure of risk and risk management has to increase quickly.
• Demand for fossil fuels may be waning. Health impacts from coal are of increasing concern, especially in China but increasingly in India. Glencore, one of the world’s largest coal producers, has lost 87% of market valuation since flotation in 2011. Arctic drilling contracts are being cancelled.
• The destabilising impact of climate change is complicating and worsening national and international security problems, as unpredictable weather events and reduced access to water and energy lead to unrest and even conflict. With indications that climate change is igniting conflict in the Middle East and elsewhere, the catalytic effect of unaddressed climate change is becoming ever more clear.
The moral imperative to act is growing. Major faith groups are openly and strongly supporting holistic, equitable, but above all, ambitious climate action. Pope Francis’ Encyclical and the Islamic Declaration on Climate Change are just two of the many calls for stewardship of the global common good.
• Technology is opening new horizons. Costs of installed solar in the US have dropped from $77/watt (£50/watt) in 1977 to $0.60/watt today. On the back of this, renewable energy has boomed. In 2013, for the first time, more renewable energy capacity was installed than fossil fuel power plants (143 gigawatts (GW) to 141GW). The estimates made by the International Energy Agency in 2000 for the amount of solar that would be deployed in 2015 was underestimated by more than 18 times, and the renewables industry is just getting started.
The net result is a world ready for change.
Political will has arrived: the 196 countries in the UN negotiations are committed to achieving an ambitious global climate agreement. There is remarkable leadership from many countries, best seen through the 146 national climate plans put forward by nations covering more than 86% of emissions. This is the beginning of a blueprint for our future.
Over the next eight weeks, until the conclusion of the Paris climate summit, I will be writing a series of blogposts in which I will explore the ways in which the world has reached the critical turning points that are finally enabling us to come together to manage the systemic threat of climate change and create a future that is made brighter by the economic, moral and political choices we are collectively now deciding to take.
We will look back at this moment as a moment of remarkable transformation, as the indisputable turning point of this century. Let us open our eyes now and see it as it happens.

Most Countries Need To At Least Double Their Efforts On Climate: Study

The Conversation - Anita Talberg & Malte Meinshausen 

To limit global warming to 2C we can’t emit more than another trillion tonnes of greenhouse gases. Burning fossil fuels is a major source. Coal power image from www.shutterstock.com

 Developed nations would need to double or triple their current efforts to limit global warming to a “safe” level of 2⁰C. That’s the finding of a study published today in Nature Climate Change assessing countries' post-2020 climate pledges ahead of December’s international climate summit in Paris.

As an example, Australia would need to reduce emissions 50-66% below 2010 levels to be considered to be doing its fair share (its current target, when converted to 2010, is a 23-25% reduction).
Countries have agreed to limit warming to 2⁰C above pre-industrial levels. But how do we divide up the necessary reductions in emissions fairly?
Developing nations often argue that developed nations need to do more, because they are responsible for more greenhouse gas emissions historically.
This new paper shows that these debates about fairness will inevitably cause us to go beyond 2⁰C, however it also shows a way to fix the problem.
You can read more in a Briefing Note, and all the underlying data is available on a new website.

Are we on track for 2⁰C?
How much the world warms is determined by the total amount of greenhouse gases that go into the atmosphere, what’s known as the “carbon budget”. To have a 66% chance of limiting warming to 2⁰C the Intergovernmental Panel on Climate Change shows that after 2011 we can only emit 1,010 billion tonnes of greenhouse gases.
Converting the budget to yearly emissions is not easy. However, by analysing hundreds of emissions scenarios, the new study found that to meet the carbon budget, global emissions need to be reduced to 1990 levels by 2030.
We are not on track for this.
The same conclusion was reached by a paper published in 2010, and more recently by Climate Action Tracker that projects 2.7⁰C of warming by 2100.

A fair share
There is a whole raft of reasons why countries’ emission reduction efforts are insufficient. One key reason is the disagreement over what constitutes a “fair” share of the global emissions-reduction effort.
In the latest stage of climate negotiations, almost every country has pledged some form of post-2020 emissions reduction target. These pledges are known as Intended Nationally Determined Contributions, or INDCs, and reflect what countries see as their own fair share.
Countries’ views differ widely, however, they can be (crudely) simplified to two broad approaches (a similar simplification is found in another recent study).
Both approaches propose that countries emit roughly equal greenhouse gas emissions per person by some future date (say 2050 or 2070). “Distributive justice” proposes that all countries start from the present and converge at some point at the same level of per-capita emissions.
However “corrective justice” seeks to correct the unfair distribution in past emissions by requiring higher historical emitters to emit less per capita in the future (and perhaps even produce negative emissions). This essentially means that all nations have an equal sum of past and future per-person emissions.
The table below shows the emissions-reduction targets required of G20 countries from either a distributive or corrective justice approach (following the specific methodology described in the study).

Dividing up emissions reductions
This chart shows targets under different justice approaches. All targets are expressed against 2010 levels.

Country	Years	Distributive justice	Corrective justice
Argentina	2025	-18%	-14%
Argentina	2030	-28%	-24%
Australia	2025	-18%	-40%
Australia	2030	-30%	-65%
Brazil	2025	-25%	-31%
Brazil	2030	-35%	-45%
Canada	2025	-29%	-48%
Canada	2030	-41%	-70%
China	2025	-19%	+3
China	2030	-32%	-4%
EU28	2025	-30%	-35%
EU28	2030	-41%	-49%
India	2025	+68%	+68
India	2030	+84%	+98%
Indonesia	2025	-32%	-26%
Indonesia	2030	-39%	-32%
Japan	2025	-39%	-34%
Japan	2030	-50%	-45%
Mexico	2025	+1%	+8%
Mexico	2030	-9%	+13
Norway	2025	-2%	-13%
Norway	2030	-13%	-23%
Russia	2025	-35%	-53%
Russia	2030	-48%	-73%
Saudi Arabia	2025	-11%	-21%
Saudi Arabia	2030	-22%	-38%
South Africa	2025	-21%	-22%
South Africa	2030	-33%	-37%
South Korea	2025	-44%	-36%
South Korea	2030	-54%	-43%
Switzerland	2025	-23%	-13%
Switzerland	2030	-33%	-20%
Turkey	2025	0%	+4%
Turkey	2030	-5%	+6%
USA	2025	-29%	-51%
USA	2030	-41%	-74%

Which should we choose?
In practice, each country chooses the justice approach that best meets its national interests. China, having a large population and low historical emissions, supports a corrective justice approach.
Australia, with a small population but high historical emissions, should prefer a distributive justice approach (although in practice Australia has never explicitly expressed a principled view of either type).
There can be no global consensus on which form of justice is most just. Unfortunately, when every country accepts to the 2⁰C target but opts for a preferential treatment of justice, global warming exceeds 2⁰C.
One way to fix this is for countries to accept more stringent targets, providing that their main trading partners are willing to do the same, in relative terms.
Australia has argued that its climate policies and emissions reduction targets are adequate because they are comparable to those of other countries — a claim that has been examined and debunked. Following this logic, Australia should be willing to increase its targets if its peers accept to do the same.

Choose your own climate pledge
Such logic underpins a new approach to international emissions reduction allocations: “diversity-aware leadership”. Under this approach, one country becomes a leader by adopting ambitious targets.
Other countries match the effort, calculating commensurate targets based on either distributive or corrective justice approaches (whichever results in a more generous allocation for each country). Ultimately, no country does any “more” than any other country, and each country is free to choose its own definition of what is fair.
Obviously, not every country is a candidate for leadership — only a major economic power with strong geopolitical pulling power. The list is probably restricted to G20 countries.
How does this play out?
Potential leadership scenarios for the EU, the US, China and Australia would be:

• To be deemed a leader, the EU would need to pledge a target of -61% on 2010 levels by 2030. To match that effort we would see these targets: US -59%, China -6% and Australia -50%
• As leader, the US would pledge -75% on 2010 levels by 2030. From this we would see: EU -50%, China -4% and Australia -65%
• A Chinese leader would pledge -32% on 2010 levels by 2030. In turn we would see: US -41%, EU -41% and Australia -30%
• An Australian leadership pledge would be -66% on 2010 levels by 2030. Matching this would require: US -75%, EU-50% and China -4%.

How this looks on global pie charts:

Meinshausen et al.

The table below compares some targets actually proposed by countries with those consistent with a fair share under the different approaches.

Climate targets: a fair share

Country	INDC	INDC (on 2010 levels)	Distributive justice	Corrective justice	Leadership
Australia (2030)	-26 to -28% (on 2005 levels)	-23 to -25%	-30%	-65	-66
China (2030)	Peak by 2030	35% above (estimate)	-32%	-4	-32
EU (2030)	-40% (on 1990 levels)	-27%	-41%	-49	-61
US (2025)	-26 to -28% (on 2005 levels)	-22 to -24%	-29%	-51	-52

Clearly, none of these country targets currently meets the criteria of a fair share, and they are all well below what might be required for leadership.

Australia needs to double or triple efforts
To claim good global citizenship, as a minimum, Australia would need to increase from 25% to 30% its current target (note: the announced Australian target uses a 2005 baseline, whereas this is compared to a 2010 baseline).
However, this would ignore the benefits Australia has gained from past emissions. Taking this into consideration, Australia’s fair share would represent a doubling (and almost tripling) of its current target. Similarly, Australia would need to almost triple its effort to be considered a climate leader.
In July 2015, the government’s advisory body, the Climate Change Authority, recommended that Australia commit to a target of -40% to -60% on 2000 levels by 2030. On 2010 levels this equates to a target of -41% to -61%. Although such a commitment would represent a significant increase in ambition, it still falls short of what might be required against the above criteria.
To read more on this paper see the Mitigation Contributions website or the Briefing Note for policy-makers.

Climate Change Seen As Top Global Threat

Pew Research Center - Jill Carle

Americans, Europeans, Middle Easterners Focus on ISIS as Greatest Danger

In advance of the United Nations Climate Change Conference in Paris this December, many publics around the world name global climate change as a top threat, according to a new Pew Research Center survey measuring perceptions of international challenges. This is particularly true in Latin America and Africa, where majorities in most countries say they are very concerned about this issue. But as the Islamic militant group ISIS maintains its hold in Iraq and Syria and intensifies its grisly public executions, Europeans and Middle Easterners most frequently cite ISIS as their main concern among international issues.
Global economic instability also figures prominently as the top concern in a number of countries, and it is the second biggest concern in half of the countries surveyed. In contrast, concerns about Iran’s nuclear program as well as cyberattacks on governments, banks or corporations are limited to a few nations. Israelis and Americans are among the most concerned about Iran’s nuclear program, while South Koreans and Americans have the greatest concern about cyberattacks relative to other publics. And apprehension about tensions between Russia and its neighbors, or territorial disputes between China and surrounding countries, largely remain regional concerns.
These are among the findings of a new Pew Research Center survey, conducted in 40 countries among 45,435 respondents from March 25 to May 27, 2015. The report focuses on those who say they are “very concerned” about each issue.1

Anxiety about Climate Change High in Latin America, Africa
Across the nations surveyed, the level of concern about different international issues varies considerably by region and country, and in some places multiple issues vie for the top spot.

Very concerned about ...

Country	Global climate change	Global economic instability	ISIS	Iran's nuclear program	Cyber- attacks	Tensions with Russia	Territorial disputes with China
U.S.	42%	51%	68%	62%	59%	43%	30%
Canada	45%	32%	58%	43%	39%	35%	19%
France	48%	49%	71%	43%	47%	41%	16%
Germany	34%	26%	70%	39%	39%	40%	17%
Italy	45%	48%	69%	44%	25%	27%	17%
Poland	14%	26%	29%	26%	22%	44%	11%
Spain	59%	63%	77%	52%	35%	39%	20%
U.K.	38%	32%	66%	41%	34%	41%	16%
Russia	22%	43%	18%	15%	14%	*	8%
Ukraine	20%	35%	9%	11%	4%	62%	4%
Turkey	35%	33%	33%	22%	22%	19%	14%
Jordan	36%	39%	62%	29%	26%	18%	16%
Lebanon	44%	39%	84%	30%	17%	18%	16%
Palest. ter.	33%	32%	54%	17%	24%	12%	10%
Israel	14%	28%	44%	53%	18%	6%	3%
Australia	37%	32%	69%	38%	37%	31%	17%
China	19%	16%	9%	8%	12%	9%	*
India	73%	49%	41%	28%	45%	30%	38%
Indonesia	42%	41%	65%	29%	22%	15%	11%
Japan	42%	30%	72%	39%	39%	32%	52%
Malaysia	37%	37%	21%	11%	20%	9%	12%
Pakistan	25%	6%	14%	9%	14%	7%	18%
Philippines	72%	52%	49%	47%	49%	38%	56%
South Korea	40%	31%	75%	41%	55%	24%	31%
Vietnam	58%	37%	30%	22%	32%	19%	60%
Argentina	57%	49%	34%	31%	28%	22%	18%
Brazil	75%	60%	46%	49%	47%	33%	28%
Chile	62%	39%	31%	31%	22%	15%	15%
Mexico	54%	46%	23%	28%	30%	16%	14%
Peru	75%	58%	35%	42%	35%	26%	27%
Venezuela	60%	60%	28%	35%	38%	22%	24%
Burkina Faso	79%	50%	41%	28%	25%	17%	15%
Ethiopia	59%	50%	38%	23%	28%	20%	20%
Ghana	71%	67%	46%	34%	42%	30%	29%
Kenya	58%	44%	35%	29%	35%	19%	20%
Nigeria	65%	48%	36%	24%	29%	25%	24%
Senegal	51%	59%	35%	33%	37%	20%	16%
South Africa	47%	33%	26%	25%	28%	18%	22%
Tanzania	49%	56%	51%	37%	46%	30%	26%
Uganda	74%	62%	39%	33%	30%	24%	23%

* Question not asked in country.

Note: Question asked about global climate change, global economic instability, the Islamic militant group in Iraq and Syria known as ISIS, Iran's nuclear program, cyberattacks on governments, banks or corporations, tensions between Russia and neighboring countries, and territorial disputes between China and neighboring countries.
Source: Spring 2015 Global Attitudes survey.

Publics in 19 of 40 nations surveyed cite climate change as their biggest worry, making it the most widespread concern of any issue included in the survey. A median of 61% of Latin Americans say they are very concerned about climate change, the highest share of any region. And more than half in every Latin American nation surveyed report substantial concerns about climate change. In Peru and Brazil, where years of declining deforestation rates have slowly started to climb, fully three-quarters express anxiety about climate change.
Sub-Saharan Africans also voice substantial concerns about climate change. A median of 59% say they are very concerned, including about half or more in all countries surveyed. Climate change is particularly worrying in Burkina Faso (79%), Uganda (74%) and Ghana (71%), while South Africans (47%) and Tanzanians (49%) are the least concerned.
Both regions are especially vulnerable to the effects of climate change, as is Asia, where a median of 41% voice great concern about the issue. Indians (73%) and Filipinos (72%) are particularly worried, but climate change captures the top spot in half of the Asian countries surveyed.

Concern about climate change is relatively low in Europe. While a median of 42% report being very concerned, global climate change is not one of the top two threats in any European country surveyed. Anxiety about this issue is highest in Spain (59%), but just 14% in Poland say the same. In a number of European nations, concern about climate change is more pronounced for those on the left of the political spectrum. Ideological differences are particularly large in the United Kingdom, where about half of those on the left (49%) express serious concerns, compared with 30% of those on the right. Those to the left of the political center are also considerably more concerned about global climate change in Italy, France and Spain.
Global climate change ranks substantially lower as a comparative global threat for Americans, with 42% saying they are very concerned about the issue. The only global issue that is even less worrying to Americans: territorial disputes between China and its neighbors (30%). Much like in Europe, perceptions in the U.S. about the threat of climate change depend on ideology. About six-in-ten Democrats (62%) are very concerned about climate change, while just 20% of Republicans say the same.

Fear of ISIS in Europe, Middle East and U.S.
Publics in 14 countries express the greatest concern about ISIS, the militant group seeking to create an Islamic state in Iraq and Syria. In Europe, a median of 70% express serious concerns about the threat posed by the growing organization. Apprehension is greatest in Spain (77%), but anxiety about ISIS is high throughout the continent. Even in Poland, where just 29% voice serious worries, fear of ISIS is second only to worries about tensions between Russia and its neighbors.
As ISIS continues to control territory in Iraq and Syria, concern in neighboring countries is high. More than eight-in-ten in Lebanese (84%) are very concerned about ISIS. Fear is especially high among Muslims in Lebanon, Syria’s western neighbor: 90% of Sunnis and 87% of Shia say they are very concerned, compared with 76% of Christians. More than half in Jordan (62%) and the Palestinian territories (54%) also express substantial worries about ISIS. Compared with other international issues, concern about ISIS also ranks highly in Israel and Turkey, which has seen a flood of refugees across its southern border as violence escalates.
A majority of Americans (68%) and Canadians (58%) are also very concerned about the looming threat of the Islamic State. In both countries, anxiety about ISIS is the top concern of the issues included in the survey. Concern is similarly high in a number of Asian nations, including South Korea (75%), Japan (72%), Australia (69%) and Indonesia (65%). Publics in all four countries cite ISIS as their top concern. Relatively few in Africa and Latin America voice serious concern about the threat of ISIS. Only in Tanzania do roughly half (51%) report substantial concerns, the highest of any country in either region.

Global Economy a Common Secondary Concern
While concerns about climate change and ISIS take the top spots in an overwhelming majority of the countries surveyed, the most frequent secondary concern around the world is the instability of the global economy. A top concern in five countries, including Russia, the economy is the second highest concern in 20 countries.
Economic instability is among the top threats in Latin America, where a median of 54% express serious concerns. Six-in-ten in Brazil and Venezuela say they are very concerned about economic issues, the highest in Latin America. Both nations have seen little to no growth in the past year, and their economic woes are expected to deepen in 2015. Economic worries are similarly troubling for countries in Africa. Ghanaians (67%), Ugandans (62%) and Senegalese (59%) are most concerned about the economy, but economic instability is considered one of the top two concerns in every country surveyed in Africa.
Russia and Ukraine, which are facing contracting economies in 2015, consider economic instability a major threat. In Russia, 43% say they are very concerned about the economy, the highest-ranking concern of any issue tested there. About a third of Ukrainians (35%) agree; economic worries are second only to their concerns about tensions with Russia.
The economy is somewhat less concerning in Europe, Asia and the Middle East. Still, a third or more in each region say they are very concerned about global economic instability, and the issue still ranks as the second-highest threat in seven countries, including some of the world’s largest economies – China, France, India and Italy all rate economic issues as one of their top two concerns.

Fewer Are Concerned about Iran and Cyberattacks
Israelis are the only public surveyed to rate Iran as their top concern among the international issues tested. More than half of Israelis (53%) have substantial concerns about the threat posed by Iran’s nuclear program. Israeli Jews (59%) are far more likely than Israeli Arabs (23%) to express anxiety.
Americans also see Iran’s nuclear program as a major issue. Roughly six-in-ten (62%) say they are very concerned, making Iran the second-highest-ranked threat of those included in the poll. While a median of 42% of Europeans express strong concern about Iran, only in the UK is it considered one of the top two dangers. Relatively few in Latin America, Africa, Asia and the Middle East say they are very concerned about Iran’s nuclear program.
Worldwide, the threat of cyberattacks on governments, banking or corporations does not resonate as a top tier worry, though there are pockets of anxiety. In particular, worries about the systematic hacking of computer networks are highest in the U.S. (59%) and South Korea (55%), both of which experienced high profile cyberattacks in recent years. Fewer than half in every other country surveyed express serious concerns about the threat of cyberattacks.

Territorial Tensions Remain within Regions
Concerns about tensions between Russia or China, and their respective neighbors, are largely limited by geography. Just 24% globally are worried about tensions between Russia and its neighbors, but in Ukraine (62%) and Poland (44%), both former Soviet bloc countries, Russia ranks as the top concern. This anxiety is high among Ukrainians and Poles from all walks of life. Within Europe, the British (41%) and Germans (40%) consider tensions with Russia to be one of their top two concerns, second only to fear about ISIS. Elsewhere, relatively few are concerned about tensions with Russia.
Similarly, while there is little concern worldwide about territorial disputes between China and its neighbors, it is one of the top two concerns in a number of Asian nations, including Vietnam (60%) and the Philippines (56%). Both countries challenge China’s claim over islands in the South China Sea, where the Chinese government has recently constructed artificial islands.

Age Differences in Most Advanced Economies

In most countries, there is little variation by age in concerns about international issues. However, in most advanced economies surveyed, people ages 50 and older are more likely to say they are very concerned about a range of issues compared with their younger counterparts, including the threat of ISIS, Iran’s nuclear program, territorial disputes between China and its neighbors, cyberattacks and tensions between Russia and its neighbors. In Canada, a majority of those ages 50 and older (55%) express serious concerns about Iran’s nuclear program, compared with just 25% of 18- to 29-year-olds. Similar differences exist in the U.S., France, the UK, Australia, Japan, Germany and South Korea for nearly all of the issues tested. Only on the issue of climate change is the opposite true in the U.S. – younger people (46%) are significantly more likely to voice concern about climate change than those ages 50 and older (36%).

1. The question asked whether people were “very concerned, somewhat concerned, not too concerned or not at all concerned” about each issue. ↩