What do you associate with climate change? Is it greenhouse gases, rising temperatures, more extreme weather or cutting the use of fossil fuels? Perhaps it's some, or even all, of these. But have you considered its likely impacts on human health?
In the experience of Anthony Leiserowitz, director of the Yale Project on Climate Communication, health is something people don't tend to link with climate change - unless they're prompted to make the connection.
When questioned in a 2011 survey about potential health risks from climate change, more than half of Americans did think global warming would cause a rise in deaths and injuries in their country from floods, hurricanes, storms and wildfires over the next 20 years, as well as heatstroke. And between 40 and 50 percent predicted there would be more malnutrition, asthma, cholera and insect-borne diseases.
Leiserowitz told a web seminar this week that climate change is often seen as a "psychologically distant problem", at least in the United States. It has become mired in debates over the science, the environmental impacts (which have focused on polar bears not people), and domestic and international political squabbling over responsibility for action.
"We ignore other frames - especially the health frame - but people do care passionately about this aspect, and it helps to localise the issue," he said. "The more local you can help people understand the impacts to be, the more likely you are to engage them effectively."
There's certainly a widespread view among experts that heath has not been given the importance it deserves in the climate change arena.
"Human health has been largely neglected, if not entirely ignored, in debates about climate change," Margaret Chan, director general of the World Health Organisation (WHO), told the seminar, adding that discussions usually focus on the economic impacts.
Now that more evidence is available on the existing and expected threats climate change poses to health, it needs to be packaged in a way that influences policy and injects greater urgency into the response, she said.
For some time, the uncertainty of the link between climate change and ill-health, and the small number of proven cases, gave the health sector little choice but to take a back seat.
But Tony McMichael, a professor at the Australian National University, said understanding of the disease burdens attributable to climate change has improved.
"We are beginning to conclude that there is a climate signal coming through," he said, adding that this will make the related health risks and stresses easier to communicate.
The effects are not just direct - deaths and illnesses caused by floods and storms, for example - but include growing secondary consequences stemming from changes in biophysical and ecological process, such as declining food yields, shrinking water resources and shifts in malaria-carrying mosquito populations. And there are mental health problems caused by conflict over scarce resources, or displacement from increasingly inhospitable environments.
But if you're looking for hard statistics, the trouble is there aren't many around and they're pretty old.
NEW WHO STATISTICS IN PIPELINE
Around 10 years ago, the World Health Organisation published research saying that the impacts of climate change since the mid-1970s may have caused over 150,000 deaths in 2000, and that a further 5.5 million healthy years of life were lost worldwide due to debilitating diseases caused by climate change. It warned that the death toll could double again in the next 30 years if trends were not reversed.
Since then, there has not been an official update.
A 2009 report from the now-defunct Global Humanitarian Forum (GHF) calculated that climate change already kills about 315,000 people a year through hunger, sickness and weather disasters, and the annual death toll is expected to rise to half a million by 2030 - but its methodology was widely questioned.
The good news is that, according to McMichael, a wide group of experts is now working on updating the WHO figures on climate-related health burdens, and is hoping to have the new numbers, examining an expanded range of impacts, ready in time for the U.N. Conference on Sustainable Development (Rio+20) in June.
The publication of this data could certainly help grab some much-needed attention.
Among those closely involved in climate change negotiations, there is at least an appreciation that health is a neglected topic. In a survey of nearly 600 delegates at the U.N. climate conference in Cancun in 2010, health scored less than 4 out of 10 in terms of its perceived importance at those talks. Yet, when asked how important it should be, the response was 8 out of 10.
Nicholas Watts, coordinator of Healthy Planet International, a medical student-led campaign that carried out the survey, said the results show that knowledge of a link between health and climate change is now established. But he believes there's a need to make things more personal and to spell out the local implications. "Health is more meaningful (to people) than carbon emissions," he said.
Another win-win strategy is to stress the co-benefits of pursuing strategies that both improve health and help mitigate climate change, experts say.
Leiserowitz of the Yale project said too much communication around climate change has used "scare appeal" to push it into the headlines. "Fear is a powerful motivator, but if you don't give people a sense that they can do something about it, it can be a negative constraint. We need to give people a sense of real solutions," he said.
For example, riding a bike or walking to work instead of taking the car boosts fitness and reduces emissions. And moving away from dirty fossil fuels to renewable energy may also ease respiratory problems linked to air pollution.
Christian Teriete, communications director of the Global Campaign for Climate Action, urged climate and health experts to think more about who they are trying to convince - whether it be doctors and nurses, or members of the public - and to tailor their message to the audience.
They should also collaborate with other climate networks to amplify their voices, and step up efforts to increase the fairly low level of media coverage on the topic. "It is as much our obligation to provide the media with more compelling angles and entry points (to the story)," Teriete said.