According to the United Nations, the world population reached the 7 billion mark on Oct. 31. More than one commentator has declared that we should “pop the champagne.” But this milestone is more cause for concern than celebration.

In the 12 years since the world population reached 6 billion, a lot has changed. In 1999, decades of rising stock values, declining commodity prices, rising incomes and continued progress in the fights against hunger and severe poverty led many to believe that there were no limits to growth. Confidence was high that we could virtually eliminate hunger and severe poverty, and it was hoped that the world would act in time to avert some of the worst effects of climate change.

Today, after a decade of economic turbulence, rising commodity prices and setbacks in the fights against hunger and severe poverty, profound questions are being raised about humanity’s future. The march of progress seems less assured than in 1999. The challenges posed by climate change and resource scarcity raise legitimate questions about the capacity of Earth to meet the needs of a growing population.

Twelve years ago, hopes were high that fertility rates would continue to fall, and that world population would begin decline by mid-century.

However, world population is still growing, with no end in sight. The United Nation’s latest projections indicate that population will reach 10 billion by 2082.

Fertility rates in many parts of the developing world are not falling as fast as once expected. While lack of access to contraceptives inhibits many women in the developing world from preventing unwanted pregnancies, other factors, such as gender inequity and child marriage, loom even larger.

Another question facing humanity is whether food production will keep pace with projected population growth. In the past five years, the world has endured two major food crises.

Food stocks have been shrinking. Prices for grains and other food staples have doubled. There is growing concern about the impact that climate change, water scarcity and fuel prices will have on food production.

Rising levels of consumption are also to blame for this growing imbalance between what we demand and what this planet can provide.

We already have 1 billion hungry people in the world. If world population, as projected, reaches 8 billion in 13 years and 9 billion in about 30 years, how many more people will go hungry?

The U.N. says food production in the developing world must double in the next 40 years to keep pace. But even if it does, food costs could keep rising, making it unaffordable for the urban poor. The world is awash with money, but severe poverty persists.

Until we’ve made more progress in eliminating hunger, reducing severe poverty and addressing climate change, let’s keep the cork in the champagne.

Robert J. Walker is executive vice president of the Population Institute, a nonprofit organization based in Washington, D.C.