(Climate change) puts some of the world’s most vulnerable people at greater risk.

The Earth needs protection and so do its people, write Marc and Craig Kielburger.

As the Brooklyn streets went dark and flooded with water, pummelled by the onslaught of hurricane Sandy, Lizbeth Lucero watched her mother pace the apartment — and pray. In the weeks that followed, her family went without power or heat. Another 760,000 were forced from their homes.

Churches provided blankets for cold nights while Lucero’s family ate hotdogs and Salvadoran pupusas donated by food trucks. Still without power at home, she returned to school and a teacher offered her a warm shower in the school’s basement. Lucero turned it down, ashamed at needing help.

We were reminded of Lucero’s story, and of those displaced from their homes or forced to flee their country as climate refugees, this Earth Day.

Hundreds of thousands of scientists and environmental advocates filled the streets in more than 600 cities, with rallies taking place on every continent — even Antarctica. Bill Nye told thousands gathered in the pouring rain in Washington, D.C., “We are marching today to remind people everywhere of the significance of science.”

The Earth needs protection — that was a central theme of the rallies — but so do its people. Experts say climate change poses the greatest security threat and mass displacements will soon be the new normal. As humancaused climate change continues to warm the planet, sea levels will rise, storms will grow stronger, floods more violent and droughts harsher. All of this puts some of the world’s most vulnerable people at greater risk.

On Earth Day, amid calls to rein in carbon emissions, end deforestation and protect coral reefs, we heard another conversation. Awareness was raised for Tuvalu, the Polynesian island at risk of disappearing into bloated waters, and action demanded for the 200,000 Bangladeshis who lose their homes each year from river erosion. The problem is complex, as are the solutions. But as with most climate issues, prevention is best. Reforestation, rehabilitating degraded land, and desalination of low coastal areas will ensure that at-risk communities are more resilient to change. Once disaster strikes, another necessary step is legal recognition for the people fleeing devastation brought on by climate change.

The United Nations Refugee Convention only extends to members of persecuted groups. People driven from their homes by rising ocean tides or creeping deserts don’t qualify for legal protection, which means many countries’ doors remain closed and safe asylum is out of reach. Some estimates say climate refugees and internally displaced people will number 50 million by 2020 and 150 million by 2050.

The helplessness she felt during the hurricane was Lucero’s spark.

It was part of what drove her to become the first person in her family of Mexican immigrants to graduate high school.

Now studying development sociology at Cornell, she carries that spark with her, a glimmer of hope that vulnerable people will not be forgotten.