The most important problems in today’s world will be solved in our lifetime.   As the development of science and technology, human beings are face with serious problem in today's world, ranging from air pollution to overpopulation crisis. Some people asserts that the most important problem will be figured out in our lifetime, while other oppose to. From my perspective, not all the problems could be solved in our lifetime. There are several reasons for saying this, as starting with three obvious reasons detailed below.   In this decades, wars have become more frequently than in the past. When people fight for power, resources, racial and religious different, it seems that we are incapable of living together in harmony. In the mid eighteenth century, the Civil War erupted when southern parts seceded from the Union in order to form their own nation. Ultimately the North got the victory, and abolished the slavery. This is a prime example of wars triggered by  racial difference. In the last decades, United States have launched several wars, including Iraq War, The Gulf War, and so forth, for the resources consist not only of resources, but also of power. All these wars cannot be exempt from our world and may continue among our lifetime throughout the rest of the 21st century.   Besides the wars, the important problem in contemporary world has correlated with the climate change which is an irreversible phenomenon in the earth. The environment problem depend upon the interplay between, on the one hand, the individual realization of protection for environment and, on the other hand, industrialization raised by the enterprises. The most dramatic example of climate change is the polar bear in the Arctic region. The cannibalism between bears is coined as the global warming, with the temperature rising and ice melting.  The reason, in the full sense of word, is the human intervention, involving the release of carbon dioxide and over industrialization as well as light pollution. In the long run, many of species would be extinct and eventually human have to reap what they have sown.   Last but not least, aging has also been a problem that we might hardly handle immediately. The overpopulation crisis are triggered in reaction to the intense competition in the world, implying that severe social problems cannot be ignored any more. Demographers worry that without change, China will become the first country in the world to age before it gets rich. The researchers also point out that it appear that the working-age population has negatively increase in recent years, demographic dividend continually decline, and  how to manage the mobile population become one of problems impeding the development of city. How to handle with falling step with the trend of aging has been the serious challenge we meet. 
In a nutshell, despite some problems have been figured out, we live in a world full of chance and challenge, there is no easy way for us to solve any problems we faced. Also, a number of measurement has been implemented in an efforts to solve those important problems.