No. That’s the short answer. But we can elaborate a bit.

It depends on what we mean by “land.” Are we talking about land on which to live? Land on which to grow things? Or land on which to grow things in an environmentally sustainable fashion? Our answers could vary on these, depending in part on whether we choose to be technological optimists or pessimists.

World population is expected to increase from its current 6 billion to about 9 billion people by 2050, at which point, given present fertility trends, it will level off. That’s a lot of people, but the earth is big, and humanity, despite our billions, doesn’t take up too much physical space. Most of the world is sparsely inhabited—for good reasons! So it’s not like we won’t be able to find a place to stand in the future. We can always build up (like we do now) or build down (which science fiction writers like to talk about). We won’t have to completely pave the earth.

The far more important question is “With all these new people, will we run out of food?” That’s the issue that underlies the writing of Malthus, who responded to a similar question 200 years ago. He said humans periodically breed too fast, and we run out of food as a result. Certainly, parts of the world are seen to run out of food on too-frequent intervals, but most economists who’ve studied famine agree that food shortages are brought on by human political failings, not by agronomic shortcomings. We grow enough food; we just don’t distribute it well enough.

But our record is not so sterling when it comes to choosing and managing land to grow food without screwing up the environment. Erosion, nutrient and pesticide pollution, degraded habitats—we’ve done them all. Doing better is not a technical issue. We know how to grow plenty of food—enough even for the expected larger world population—and we know how to do it without making future generations worse off. Putting it all together is a matter of political will and prudent economic analysis.

For an interesting discussion of this topic, check out wikipedia.com's article on ecological footprint.

– Steve Taff, Associate Professor in the Department of Applied Economics

Many species of mosquitoes bite humans and other vertebrates to suck blood. Biting mosquitoes can be annoying, and can also serve to spread pathogenic organisms, including those that cause malaria, dengue, filariasis, dog heartworm, and many other forms of illness. Because of their blood sucking and disease spreading habits, few people would think that mosquitoes have any redeeming value.

From a broader perspective, however, mosquitoes occur in terrestrial and aquatic communities, where they can be viewed as useful members of food webs. Adults visit flowers, feed on nectar, and may pollinate flowering plants. Adult mosquitoes also serve as food for other insects, birds and bats. Mosquito larvae occur in swamps, marshes, floodwaters, and even small containers such as tree holes and pitcher plants. Larvae of most species graze on particulate matter such as bacteria, protozoa and algae, and their activity may assist in decomposition of submersed plant matter. Larvae are also food for many predatory insects, fish, amphibians and waterfowl. A challenge for researchers is to find ways to prevent mosquito-borne diseases without causing unwanted side effects in the natural environment.

–Roger Moon, Professor, Department of Entomology

Yes. In the fruit crops we have breeding programs in apples, grapes, strawberries and blueberries. In the last year Zestar! apples, a tasty, juicy, early-season variety, have become available to Minnesota consumers. Trees of SnowSweet apples became available in 2006. This is an October apple with a rich, sweet flavor, and a firm, snowy white flesh.

In addition to the apples, Marquette grape was introduced in 2006. This grape makes as spicy and complex red wine. It joins previous recent wine grape introductions Frontenac (1996), La Crescent (2002), and Frontenac gris (2003) that have formed the basis for a rapidly expanding local wine industry in the Upper Midwest.

The Itasca strawberry was also introduced in 2006, an early June variety that will be planted by local strawberry growers and gardeners.

Also, the University has developed several disease-resistant lines of potatoes in the past and has three or four new varieties that will be released in the next year or so. These varieties are resistant to cold sweetening, which causes potato chips and French fries to turn dark colored and have bitter flavor. Two of them – currently called 'MN 99380-1' and 'MN 15620' – have yellow flesh, which is important for antioxidant activity, total phenolic content, and increasing Vitamin C.

–Jim Luby, Professor, and Christian Thill, Associate Professor, Department of Horticultural Science

The easy answer is: donate money to a large international conservation organization. However, it may not be satisfying to a small donor to watch his/her gift disappear into an amorphous pool of donations. Our tiger research lab at the University of Minnesota, consisting of myself and Ph.D. students, decided to turn this question around and ask, "What can we do to help people save species like the tiger?"

In posing this question, the challenge is to come up with a meaningful strategy for people no matter the size of their donation. A schoolgirl giving $10 or a doctor donating $5,000 both want to make a difference. The answer may lie in a web technology called "wiki" where people come together in a social network to address an issue. What if a website were established that described ongoing tiger projects throughout Asia? People could respond by exploring funding options on this site and select a project to support. For example, schoolchildren might pool funds to donate a single $150 GPS to help with a tiger survey. The wiki website could have a picture of a ranger in Thailand using the GPS and include the names of the children making the donation. Another group might donate a satellite collar for a project in Bangladesh, while a single individual could purchase a solar panel system to power a park radio in Cambodia.

I thank the person who wrote this question. You challenged us to address two important questions: how to make donations for conservation meaningful and how to link citizens in the United States with people undertaking conservation in Asia. Motivated by your question, we will develop a website for tiger conservation; if you want to help us start, contact me at jlds@umn.edu.

–David Smith, professor, Department of Fisheries, Wildlife and Conservation Biology

Yes. It is certainly possible, within the near future, to run our cars, heat our living rooms and make many of the products that we use in our everyday lives from things that we grow, in Minnesota. At the Department of Bioproducts and Biosystems Engineering, we are looking into ways to convert bio-resources like forest and agriculture residues into many products. Our approach relies on using multiple technologies, using computer modeling and laboratory experimental data, to produce fiber for paper and building materials, energy for heating our homes and liquid fuels like ethanol for our cars and plastics and more. We are studying the optimum combination of technologies and processes that can be used, much like the petroleum refineries of today, in a more effective and sustainable manner.

–Shri Ramaswamy, Professor and Department Head, Department of Bioproducts and Biosystems Engineering

You can counteract global warming by using energy efficient appliances and vehicles with high gas mileage, and planting trees. It's too late to stop global warming, but we can slow the rate of warming which will give the economy and ecosystems time to adapt to the changes. If global warming becomes severe, other measures may be necessary such as albedo modification--in essence making the earth brighter in color to reflect more sunlight and prevent temperatures from going up as much. This may buy time to deal with the CO2 emissions, which will probably take more than a century, since it requires a switch to sources of energy other than coal and oil.

– Lee Frelich, Research Associate, Department of Forest Resources, and Director, The University of Minnesota Center for Hardwood Ecology

Not surprisingly, there isn’t a wealth of research information on how birds respond to severe weather—researchers are frequently too busy responding to severe weather themselves to make detailed observations of birds. We do know that birds tend to move closer to the ground and under cover (e.g., in dense bushes) when they encounter severe winds and weather, and they work hard to remain facing into the wind. If the wind comes from behind them it will catch the feathers and lift them up, allowing rain to get underneath. Properly-arranged plumage is well oiled and sheds water efficiently—but a truly wet bird is unlikely to survive a storm.

It is very likely that some birds do get blown out of their hiding places and die during severe storms. We don’t know how common this is because the necessary research (which would be logistically difficult) hasn’t been conducted.

– Scott Lanyon, Director, Bell Museum of Natural History and Professor, Department of Ecology, Evolution, and Behavior

Spiders are amazing silk engineers. They make many different kinds of silk for different purposes. They use a strong, non-sticky silk for the main components of their webs and another kind of silk for capturing their prey. They don’t get caught in their webs because they walk on the non-sticky silk or lower themselves on a separate silk line, carefully avoiding the sticky. Humans are studying how to make artificial spider silk because it is so strong and light. In fact, the Department of Defense is interested in practical applications of artificial spider silk.

–Susan J. Weller, associate professor, Department of Entomology and curator of Lepidoptera, Bell Museum of Natural History

Sweet foods are innately palatable. For example, infants demonstrate a characteristic facial expression after drinking sweet fluids, an expression associated with pleasure. On the other hand they grimace after ingesting a bitter solution.

In addition to changes in expression, humans and rats will work harder to obtain a sweet food than an unsweetened diet. Sweet substances affect some brain chemicals and the rewarding centers in the brain. Such involvement of reward centers make palatable foods very rewarding. Mixtures of fat and sugar are even more palatable to humans and animals, and such combinations of macronutrients are often referred to as junk food. They are called junk foods because they provide little more than energy, something not particularly healthful in an overweight or obese population. Healthier foods contain fats, carbohydrate and protein; but also are rich in micronutrients such as vitamins and minerals and other beneficial substances.

The food industry has and continues to work on foods that taste good, and are also healthy; however, more efforts are needed. We need foods that are low in caloric density, high in nutrients and still taste great.

– Allen Levine, Dean of CFANS

These birds are just doing the avian equivalent of a NASCAR driver’s slipstreaming (or drafting). Geese and ducks are relatively large birds, and they affect the air they fly through just as a race car does. Each bird creates a slight uplift at the tips of their wings during flight. By flying behind and slightly above another bird’s wing tip, birds experience an updraft. These trailing birds gain an advantage and expend less energy than they would if they were flying by themselves. Studies have shown that a bird in a flock flying the same speed as a bird flying alone flaps its wings half as often.

– Scott Lanyon, Director, Bell Museum of Natural History and Professor, Department of Ecology, Evolution, and Behavior