Earth Day has made a long, strange trip from its beginnings in 1970.

The first Earth Day was an outgrowth of the counterculture of the 1960s, triggered by an oil spill off the California coast and brought to life by a Democratic senator and a Republican congressman as a series of “teach-ins” on the environment. The scope was national, but the focus was largely local: millions headed to U.S. parks, universities and city streets to raise awareness about the pollution of air and water, the destruction of wild places—and the loss of wildlife that inhabited them.

This same era of social upheaval saw the birth of another movement: the push to end extreme poverty. As the United States worked to bring more prosperity to its neediest through laws known collectively as the War on Poverty, the United Nations and global financial institutions including the World Bank worked to aid the world’s poorest.

Since then, these two crucial drives—to alleviate poverty and protect the environment have moved forward on parallel tracks. That needs to change, and this year’s Earth Day highlights a new direction: its theme is global citizenship, with a goal of economic growth and sustainability.

The idea of linking these two agendas isn't new, but the urgency is.

The turn of the 21st century saw the crafting of the Millennium Development Goals, a set of targets meant to alleviate extreme poverty in the developing world. They mentioned environmental issues, but the environment was an afterthought – a goal with no real connection to the rest of the anti-poverty agenda. Development projects generally aimed, at most, at minimizing environmental impact.

Meanwhile, the scientific community, including the UN Intergovernmental Panel on Climate Change, has provided increasingly stark evidence that the climate is changing and that human activities, notably the burning of fossil fuels, are a key driver of that change. Beyond sophisticated computer models, a number of trends tell the tale: 2014 was the hottest year globally in the modern record. The first three months of 2015 were also the hottest January, February and March on record. Arctic sea ice, another indicator of a warming planet, was at its lowest March extent ever, according to the U.S. National Climatic Data Center.

While the global community has moved forward, it is not yet doing enough to meet the challenge. Global heat-trapping emissions continue to rise, ratcheting up the impact of a changing climate on countries least able to respond to it. The world is heading toward a new climate agreement in 2015, and it will take that and more to prevent the planet from heating up beyond 2 degrees C (3.6 degrees F) over pre-industrial levels.

The problem with the development community and the environmental community going their own ways is that neither one of these giant problems can be solved without solving the other.

There are hopeful signs that these two communities recognize their agendas are inextricably linked. International negotiators are working on a new set of development goals that aim to lift the poorest out of poverty while sustaining a healthy environment. These Sustainable Development Goals are expected to be agreed upon in September and support a global climate agreement in December in Paris. The World Bank and many other development banks are positioning themselves to tackle global environmental sustainability challenges.

Perhaps Earth Day is the right time to ask some tough questions about how these agendas can move from commitments to concrete action.

Let’s ask the development community whether it is collectively willing to take the actions needed to tackle climate change, recognizing that if it doesn't, greater poverty could be the result. To finance and planning ministers, those keen to promote growth to reduce poverty and economic inequality, are they fully cognizant of the challenges posed by an unsustainable world? And are they willing to embrace policies equal to this challenge?

Let’s ask environmentalists if they have fully taken into account the plight of the world’s poorest people, and made sure that environmental policies can help improve, not harm, their livelihoods? For example, do their plans to conserve biodiversity also support and improve human lives? Have they been truly honest about the negative impact some low-carbon solutions could have in the short-run on poor people? The New Climate Economy report sheds light on this topic showing that countries at all income levels can build lasting economic growth while reducing the risk of climate change—if they act now, based on the most accurate data.

When tens of thousands gathered on the National Mall on April 18 in a pre-Earth Day concert and rally, there were pop stars and speeches on a brilliant spring day, all aimed at building momentum for environmental sustainability and economic growth that work together. It was a far cry from the movement that began in the tie-dyed days when the environment was a new term and fixing it required protecting a local stream or picking up litter along a highway.

The rest of 2015 offers the world a great challenge and a greater opportunity to join the environmental and economic growth agendas. Let’s look for a clear-eyed realization that you can’t tackle poverty and spur economic growth without protecting the environment, and you can’t protect the environment without finding ways to make the economy grow while improving people’s lives.

Happy Earth and Prosperity Day.