The following text is for question 83 - 86

Text 3

    Perhaps even more problematic to human welfare in the coming century than a further decrease in the availability of fresh water is the impact of climatic disruption on the supply of food. As with water, global access to food is already questionable. In 2009, the number of people suffering from protein-calorie malnutrition exceeded 1 billion after reaching a low of around 830 million in the 1990s.

    In poor countries around the world, malnutrition underlies roughly one-third of the entire burden of disease. And roughly 2 to 3 billion people already suffer from micronutrient deficiencies.

   Looking forward, farmers around the world will need to double agricultural production by 2050 in order to keep up with demand from a growing and more prosperous human population that prefer a more meat-based diet. This doubling of output will need to occur despite problems already found in agricultural productivity. Water scarcity, as discussed above, is a major constraint to increasing agricultural production. In addition, roughly one-third of the Earth's and surface suffers from land degradation from the combined effects of soil erosion, salinization, nutrient depletion, and desertification.

    Finally, the rise of the biofuels industry is generating enormous demand for grain. By increasing grain demand and, as a consequence, demand for arable land and irrigation, growing grains as biofuels feedstock will be deemed more important than human food needs. Thus, growing grains for biofuel needs an immediate banning action.

   Amid rapidly rising demand for food, increasing environmental pressures on food production, and growing human malnutrition, climate change additionally compromises both agricultural yields and the nutritional quality of the crops produced. Agricultural productivity is well known to be sensitive to changes in growing season temperatures. Observational, longitudinal, and modeling studies all confirm that a 1 % rise in temperature corresponds to roughly a 10% reduction in yield of the major grains. As temperature rise 2 - 6°C over the next century, the reduction in agricultural yield will depend, in part, on our capacity to adapt and in part, on how temperature variability changes; but, in general, yields are expected to drop.

(Diadaptasi dari http://www.ncbi.nlm.nih.gov/pmc/articles/PMC 3042309/)

Which of the following is the restatement of the sentence, 'Agricultural productivity is well known to be sensitive to changes in growing season temperatures.' (the last paragraph)?