1. Article Review – ‘Perception of Climate Change’ by Hansen et al.
This article investigates the phenomena climate change and its aim is to use statistical data to support that climate change is real. An aspect of climate change named as ‘climate dice’ is mentioned in the article which referred to the chance of extreme weathers such as unusually cool or warm seasons. In the past three decades, there has been evidence of increasing climate dice ‘loading’ occurring at the same time as there is an increase in global warming compared to what was expected. Given this observation the public may not necessarily recognise this as global warming because people tend to perceive that climate patterns are constantly fluctuating.
The essential research question is to investigate whether the change in the temperature anomalies over the past 30 years have been more extreme measured by standard deviation compared to the usual weather pattern variations. This research was carried out by James Hansen, Makiko Sato and Reto Ruedy from the National Aeronautics and Space Administration Goddard Institute for Space Studies and Columbia University Earth Institute to establish that climate change is happening. The primary focus is to discuss the practical implication of the issue climate change regarding its trends and patterns over the past decades.
The Goddard Institute for Space Studies (GISS) surface air temperature analysis was used to examine the variation of the seasonal mean temperatures. The observation records for surface air temperature at meteorological stations were used in the analysis. This data was available from the Global Historical Climatology Network (GHCN) and maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Climatic Data Centre (NCDC). Despite the release of version 3 of GHCN which yielded a larger global warming trend of 0.75°C as opposed to the trend for version 2 of 0.72°C, version 2 was used as it was employed in the GISS analysis. Two separate spatial resolutions, 1200km and 250km, which refer to the size of the smallest objects resolved on ground were tested out and the 250km was found to be most suitable for analysis.
The research chose 1951-1980 as the base period primarily because it consisted of a relatively stable temperature which was within the Holocene range. The main findings were illustrated through a series of graphs depicting the temperature distribution from various time periods.
The principal findings include the immense change in seasonal mean temperature anomalies in the past three decades particularly during summer with its distributional values shifting one standard deviation higher. In contrast with the base period 1951-1980, the seasonal distribution of both the mean temperature and range anomalies have increased resulting in warmer climates. As such extreme anomalies, that are, temperatures at least three standard deviations above the predicted, particularly in the areas of Texas in Moscow were due to global warming because in the absence of it these extreme anomalies would be exceptionally rare. In recent years these extreme anomalies occurred in 10% of global land area as opposed to the period of climatology where only a few tenths % of global land area was affected.
The research conducted has significance as it demonstrated the distinction between the weather patterns and trends from various time periods. Based on the information given from the article, there is substantial evidence to support the extreme weather patterns in recent decades. However, the research only examined one base period and further study will be required to demonstrate that the extreme weather is not just cyclic occurrence but a general increasing trend.
2. Possible causes of climate change
Climate change is a highly controversial issue within the science community affecting the growing crisis in relation to the world economy, food