US EPA

7872922 

Journal Article 

Past and future climates in the tropical rainforest region of north Queensland 

Suppiah, R; Bathols, J; Macadam, I; Whetton, PH 

2009 

2064-2070 

WOS:000290045002017 

Tropical rainforest regions of north Queensland cover less than 1% of Australia"s landmass but contain a highly disproportionate amount of the biodiversity. Extensive research on climate impacts on this biodiversity is being undertaken through a major research initiative, the Marine and Tropical Sciences Research Facility (MTSRF), coordinated by the Reef and Rainforest Research Centre (RRRC) in Cairns and Townsville. Results presented in this paper are based on the work carried out for the MTSRF. Temperature in the tropical region has increased steadily between 1950 and 2008, but shows strong decadal and inter-annual variations. Since 1950, the tropical rainforest region"s average maximum temperature has increased by 0.76 degrees C (0.12 degrees C per decade), the minimum by 0.79 degrees C (0.14 degrees C per decade) and the average by 0.78 degrees C (0.13 degrees C per decade). Cooler temperatures during the last few years have reduced the warming rate in this region. Variations in annual and seasonal rainfall in the rainforest region of north Queensland during the past century show no clear trend, but indicate fluctuations on multi-decadal time scales. In particular, the 1920s, 1960s and 1990s were dry decades and the 1970s was a wet period. Decadal fluctuations in annual rainfall are dominated by the wet season (January to March) rainfall variations. Rainfall in the dry season (August to October) shows strong variability. Rainfall in transitional seasons (Transitional 1 - November and December; Transitional 2 - April to July) also shows strong variability. The relationship between the Southern Oscillation Index (SOI) and rainfall is positive, but shows decadal-scale variations. The relationship was weak during 1930s and also during 1980s. The tendency for a weakening relationship in recent years began after the mid 1970s. Projected changes in annual average temperature, rainfall and potential evaporation for decades from 2020 to 2080 for the three regions of were calculated, but annual values for 2030, 2050 and 2070 are described in detail. More details of temperature and rainfall projections for seasonal values and also for various decades from 2020 to 2080 are given in Suppiah et al. (2008). Projections were given for the 50(th) percentile as the best estimate and low and high ranges are given as 10(th) and 90(th) percentiles of temperature, rainfall and potential evaporation changes. The projections show that the inland areas of the MTSRF region will warm faster than the coastal areas. For a medium (AIB) emissions scenario the best estimate regional annual average temperature increase by 2030 is 0.8 degrees C with a range of uncertainty of 0.6 to 1.1 degrees C. Higher increases are projected for 2050 and 2070. For 2050, the ranges of uncertainty for regional average temperature increase for the different scenarios and span the range 0.7 to 2.2 degrees C. The corresponding range for 2070 is 0.9 to 3.5 degrees C. Rainfall changes are more complex than temperature changes and show increases and decreases. For a medium emissions scenario the best estimate or the 50th percentile regional average rainfall change for 2030 is -1% with a range of uncertainty of -8 to +6%. Changes by 2050 and 2070 are dependent on emissions scenario. For 2050, the ranges of uncertainty for regional average rainfall change for the different scenarios span the range -16 to +11%. The corresponding range for 2070 is -26 to +18%. Percentage rainfall changes in Dry season and Transitional season 2 are greater than those for Wet season and Transitional season 1. Projected changes in potential evaporation (PE) indicate an increase. By 2030, the best estimate for PE change is 3% with the uncertainty range from 0 to 6%. By 2050, the increase in PE is 6% with a range between 3 and 10%. The change for 2070 is 8% with a range from 3 to 14%. 

Climate change projections; tropical rainforest; Marine and Tropical Sciences Research facility (MTSRF)