Global warming isn't just destroying the environment, endangering our coastal cities and threatening countless animal and plant species.

A new report from the World Bank warns that climate change is such an imminent threat that rising sea levels could "drive more than 100 million people" into extreme poverty in the next 15 years. Among the regions that are most at risk are sub-Saharan Africa and South Asia, where crop losses and food price spikes could have a huge impact on agriculture, which is the main source of income for most poor families.

By 2030, the report warns, "crop yield losses could mean that food prices would be 12 percent higher" on average in sub-Saharan Africa, which could strain poor households who spend as much as 60 percent of their income on food. In addition, an estimated 48,000 children under age 15 could die from diarrheal illness by 2030 due to a global warming of 2-3°C, which could raise the risk of malaria by up to 5 percent.

The report, "Shock Waves: Managing the Impacts of Climate Change on Poverty," does have a ray of light, though. It notes that if poverty reduction and development work continue, it could help save many of those at the most risk. Among the potential efforts that could help people deal with climate shocks are early warning systems and flood protections as well as heat-resistant crops.

But That's Not All

In addition to the potential huge impact on the most vulnerable, a report from Climate Central found that rising sea levels caused by a 4°C increase in warming from carbon emissions could "submerge land that is currently home to up to 760 million people." Among the cities most threatened by this possible rise in sea levels are: Hong Kong, Mumbai, Jakarta, Shanghai and Hanoi, with China carrying the most people at risk of costal inundation at 145 million.

The U.S. is the second most threatened nation outside of Asia, with around 25 million people living on lands that could end up under water.

Greenhouse Gases Reaching All-Time Highs

Those dire warnings came at the same time as disturbing new figures from the World Meteorological Organization, which found that carbon dioxide levels have passed a red line of no return this year, crossing the "symbolic threshold" of 400 parts per million across most of the Earth.

"We can’t see CO2. It is an invisible threat, but a very real one. It means hotter global temperatures, more extreme weather events like heatwaves and floods, melting ice, rising sea levels and increased acidity of the oceans," WMO Secretary-General Michel Jarraud said in a statement. "This is happening now and we are moving into unchartered territory at a frightening speed." It marked the first time that carbon dioxide levels have exceeded 400 ppm since record-keeping began.

The WMO also noted that the concentration of the most dangerous greenhouse gases -- carbon dioxide, methane and nitrous oxide -- had a 36 percent increase in the warming effect on our climate between 1990 and 2014. This year is already on track to surpass 2014 as the hottest year in recorded history.

"Every year we report a new record in greenhouse gas concentrations," Jarraud added. "Every year we say that time is running out. We have to act NOW to slash greenhouse gas emissions if we are to have a chance to keep the increase in temperatures to manageable levels."