Dry/wet years alter frequently
The amount of rainy days decreases, whereas the intensity of precipitation becomes higher. From recent 30 years, we can see that 0.99 day with extremely heavy rain (daily rainfall greater than 130 mm) and 1.36 days with torrential rain (daily rainfall greater than 200 mm) are increased in Taiwan every 10 years. With an increasing amount of days with torrential rain, it is likely that numerous threats will be brought. For instance, there will be more floods in lower terrains, more landslides and falling rocks in the mountains.
Besides the variation of precipitation, as global warming is becoming an inevitable trend, phenomena such as rising temperature and sea level also occur in Taiwan. In the past one hundred year, the mean temperature in Taiwan has increased 1.3 °C, which was not only higher than the global mean, but also our vicinities such as Japan and China. In recent 30 years, the annual mean temperature of Taiwan continues to rise approximately 0.29 °C every 10 years. This is particularly obvious in northern and central Taiwan. The sea level around Taiwan continues to rise unceasingly. Between 1993 and 2003, the sea level rose 5.7 mm every year, which means that it has risen 3.1 ~ 4.5 cm on average so far. This was also higher than the mean in AR4 report published by IPCC. The gradually rising sea level has been turning Taiwan “thinner and thinner” inconspicuously.