Changes in climatic conditions influence our living environment. Today, changes in our climate mean we are rapidly moving towards a warmer environment. The warming is already having an influence on our living environment.
Scientists believe the warming is caused by human activities. During the last 50 to 100 years, increasing industrialisation and human activity (such as burning fossil fuels for transportation and electricity generation) have begun to affect the proportion of greenhouse gases (e.g. CO2, CH4, N2O) in the Earth’s atmosphere. Greenhouse gases act in the same way as a greenhouse – trapping in the heat. The increased amount of greenhouse gases in our atmosphere causes the Earth to heat up at a fast rate. This is known as global warming. Since this warming will also affect our weather patterns and climatic conditions, we refer to it as climate change.
Climatic change alters rainfall, temperature and weather patterns. Overall, there are likely to be more weather extremes in the Bay of Plenty. Scientists predict the global temperature would still rise even if we now stopped all the human activities that cause the warming. If we continue with business as usual, the impact is likely to escalate. These changes are likely to impact on our native ecosystems, farming, forestry, horticulture, industry, infrastructure, health, biosecurity and our economy.
Climate change is a worldwide concern. Governments, including our own, have recognised the contribution of human activity to changing climatic conditions, and have agreed to take action. The Government now requires that councils and others have particular regard to the effects of climate change when carrying out their functions.
|So, what is the Bay of Plenty's climate?|
This region has a climate with warm humid summers and mild winters. Typical summer daytime maximum air temperatures range from 22°C to 26°C, but seldom exceed 30°C. Winter daytime maximum air temperatures range from 9°C to 16°C. The sea influences air temperatures considerably in the coastal areas and sea surface temperatures on the east coast are the warmest in New Zealand. The region has one of the sunniest climates in the country. Annual sunshine hours average about 2000 in many areas. Coastal areas, for example from Tauranga to Whakatane, are much sunnier with at least 2200 hours, and dry spells are common.
Southwest winds prevail for much of the year. Sea breezes often occur on warm summer days. Winter usually has more rain and is the most unsettled time of year. In summer and autumn, storms of tropical origin may bring high winds and heavy rainfall from the east or northeast.
Prediction from the New Zealand Climate Change Office
Climate scientists estimate that the Bay of Plenty's temperature could be up to 3°C warmer over the next 70–100 years. This compares to a temperature increase in New Zealand during the last century of about 0.7°C. To put this in perspective, the 1997/98 summer, which many New Zealanders remember as particularly long, hot and dry, was only about 0.9°C above New Zealand's average for the 1990s.
Flooding could become up to four times as frequent by 2070, together with a sea-level rise of between 30 cm and 50 cm by 2100.
Source: New Zealand Climate Change Office, Ministry for the Environment
For more information on climate change and what we can do about it, see the website: www.climatechange.govt.nz, email email@example.com or phone 0800 WARMING.
The mean annual rainfall is predicted to decrease by around 1%–4% by 2030. However due to the Interdecadal Pacific Oscillation (IPO, with a typical return period of 20 to 30 years), climate change is likely to increase the frequency and intensity of heavy rain events in the region. In general, the change varies with seasons and geography. There will be drier springs and summers and slightly wetter winters. Coastal areas are likely to be drier.
In the Bay of Plenty, temperatures are expected to increase. There are different predictions for future temperatures in the Bay of Plenty reflecting the variation between seasons and across locations. The mid-range temperature prediction in the Bay of Plenty is for an increase of 0.8˚C by 2030 and 1.8˚C by 2080. The ranges of the temperature and rainfall predictions are shown in the following table:
Projected Changes for the Bay of Plenty area in seasonal and annual average temperature (in ˚C) and precipitation (in %) Source: NIWA
| Temperature ° C
0.0 to 1.2
0.3 to 3.8
0.0 to 1.3
0.4 to 3.9
0.4 to 1.6
0.8 to 4.2
0.2 to 1.2
0.4 to 3.6
0.2 to 1.3
0.5 to 3.8
| Precipitation %
-10 to +4
-7 to +19
-16 to +4
-18 to +15
-5 to +7
-2 to +9
-20 to +8
-9 to +2
-15 to +2
Since the early 1900s, average temperatures have risen by about 1˚C. The Bay of Plenty recorded very high temperatures in the 1990s. Between 1951 to 2000, the seasonal temperatures along the coast increased by up to 0.2˚C every 10 years. In coastal places, Tauranga for instance, the number of frosts has decreased significantly. The record shows that cold nights have significantly warmed since 1940 (an increase of 0.3˚C every 10 years).
In the medium to long term we can expect temperatures in the Bay of Plenty to become similar to those presently experienced in Kaitaia in the far north.
In the next 50 years, the mean westerly wind component across New Zealand is expected to increase by 10% of its current value. Increasing westerlies are one reason for a drying trend in the Bay of Plenty. Strong winds are expected to be more frequent with the warmer climate together with an increase in the frequency and intensity of low-pressure systems.
Climate trends in recent decades may already be affecting the health of New Zealanders, but any such effects are difficult to demonstrate unequivocally because it is often difficult to separate the effect of changes in climate from the effects of changes in other social and environmental conditions. The impact of climate change depends on the extent and rate of warming, and on how well individuals and society can adapt. A study commissioned by the Ministry for the Environment shows that climate change can affect human health both directly (temperature extremes and heavy rainfall) and indirectly (water supply, pollen causing allergy, ozone depletion, infectious diseases carried by animals or insects, and stress).
Changes in climate are likely to influence primary industries as production is often influenced by climate conditions. The Bay of Plenty’s primary production (agriculture, forestry and fishing industry) covers 45% of the land and involves over 10% of its labour force. On the other hand, there may be economic opportunities through the introduction of new commercial crops.