An AIDS activist and an environmentalist sit together in a room, yetonly one chair is occupied. How is this possible? You could concoct anynumber of theories (the AIDS activist sits on the environmentalist’slap; one person sits on the floor). But as with all brainteasers, thesimplest answer is typically overlooked: The AIDS activist and theenvironmentalist are one and the same.

Today, the worthy causescompeting for our attention can seem endless. In an era where budgetsto address a variety of global concerns are stretched ever thinner asresources shrink, and as the number of people around the worldsuffering from a variety of ills seems to expand every day, it’s nosurprise that the battle to secure funds to address any crisis isheating up. The resolution to any one crisis may, these days, lie inattacking several at once. HIV/AIDS and environmental challenges mayseem worlds apart, but seeing the connections between them may provideinsight as to how to better fight them. Policymakers are starting tocatch on. The recent President’s Emergency Plan for AIDS Relief(PEPFAR) reauthorization bill that was passed by the House ofRepresentatives specified that $9 billion of the $50 billion allocatedin the bill go toward fighting tuberculosis and malaria—two diseasesthat often affect HIV-positive people in the developing world.

Researchersare quickly beginning to appreciate the interconnectivity of theworld’s largest crises. For example, officials recently logged recordrates of HIV infection in Nagaland, an Indian state bordering thecyclone-ravaged nation of Myanmar, and some HIV-positive people inMyanmar struggled to access treatment well after the storms. Indeed,it’s impossible to examine any one cause without understanding howother causes affect it.

Australian researchers recently madeheadlines by saying that global warming and HIV could be closely tied.In his treatise A World Free of HIV, Daniel Tarantola, a professor ofhealth and human rights at the University of New South Wales, inSydney, argues that global warming could help boost new HIV infectionsand worsen conditions for poor people already living with the virus.

“Climatechange is likely to have additional effects on our vulnerability toHIV,” writes Tarantola. “Climatologists foresee that within the nextdecades, vast areas will be affected by extreme natural disasters, somelost to rising waters and others, in Africa in particular, by expandingdesertification.”

The implications are many. Access to cleanwater is already a treatment barrier for people with HIV in thedeveloping world, and global warming will exacerbate the problem.People without access to a balanced diet or proper fluids may find thatthey can’t tolerate their meds and may skip doses, which can lead todrug resistance. Also, HIV-positive mothers with limited food sourcesmay be tempted to breast-feed hungry children, even if they realize therisk of mother-to-child transmission.

Tarantola argues that theeffects of global warming will put people at greater risk forcontracting HIV, saying, “There is ample evidence that the unattendedneeds of uprooted communities and widening economic disparities withinand across populations fuel vulnerability to HIV.” For example, asresources become more limited, people are likelier to engage in sexwork to secure food and shelter for their families.

HIV-positivepeople in the U.S. aren’t immune to the effects of global warmingeither. Rising gas prices are already swallowing budgets for insuranceand health care. As Hurricane Katrina demonstrated, extreme weatherconditions can separate Americans from meds, care and counseling. Inthe U.S. and around the world, global warming—which leads to volatileweather, changes in crop yields and lack of potable water—will make itmore difficult to establish infrastructures for people who most needcare.

Perhaps in an ideal world, we’d have the time andresources to address all global health concerns, such as HIV, on amacro level, taking a multitude of factors into account. But in ourvery real world, the lesson is to try to keep a larger perspective onhow combating societal issues—poverty, gender inequality, fuelconsumption—can also play a role in beating AIDS.

“The lessonslearned from [fighting] HIV have given rise to a new understanding ofpublic health where it makes no sense to oppose a public healthapproach to HIV [in lieu of] a human rights approach: They are stronglybound to each other and both aim at achieving greater justice, greaterwell-being and dignity,” Tarantola writes. “The synergy between health,development and human rights needs to inform international developmentpolicies and programs.” Now, there’s a bright idea.