Data - Page 9

Soil erosion reduces the productive capacity of land. Sediment entering waterways affects water quality, storage capacity, and biodiversity. Soil erosion in the North Island is primarily due to the historical clearance of forest on steep slopes for pastoral agriculture. South Island soil erosion is primarily due to high rainfall and steep mountainous terrain.

Column headings:
vol_tkm2yr = volume of soil lost per year measured in tonnes per square kilometer

This dataset relates to the "Estimated long-term soil erosion" measure on the Environmental Indicators, Te taiao Aotearoa website.

Growing degree days (GDD) measures the amount of warmth available for plant and insect growth and can be used to predict when flowers will bloom and crops and insects will mature. GDD counts the total number of degrees Celsius each day is above a threshold temperature. In this report we used 10 degrees Celsius. Increased GDD means that plants and insects reach maturity faster, provided that other conditions necessary for growth are favourable, such as sufficient moisture and nutrients. As a measure of temperature, GDD experiences short-term changes in response to climate variations, such as El Niño, and in the longer-term is affected by our warming climate.
This dataset gives the number of GDD per month and calendar year for all 30 sites.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

New Zealand’s indigenous and exotic forests absorb and store carbon from the atmosphere through photosynthesis. As forests grow, the carbon stored in them increases. These carbon stocks help offset greenhouse gas emissions from sources such as agriculture, energy production, and transport.

Column headings:
type = vegetation type of forest
vol_tC = volume of carbon in tonnes

This dataset relates to the "Estimated forest carbon stocks" measure on the Environmental Indicators, Te taiao Aotearoa website.

Detailed New Zealand greenhouse gas emissions data for 1990 and 2015 for Energy and Agriculture sectors. Data are sourced from the 1990–2015 New Zealand Greenhouse Gas Emissions Inventory. Includes sub–sub–sector data. Emissions are in kt and have not been standardised by conversion to CO2 equivalents. Greenhouse gases (GHGs) absorb heat from Earth’s surface, warming the atmosphere and changing our climate. New Zealand’s share of GHG emissions is very small, but our gross emissions per person are high. Emissions mainly come from combustion of fossil fuels that emit carbon dioxide (CO2), and agriculture which emits methane (CH4) and nitrous oxide (N2O). Carbon dioxide remains in the atmosphere much longer than other major GHGs. Because of this, today’s global CO2 emissions will continue to influence atmospheric CO2 concentrations for a very long time. Methane and N2O trap heat better than CO2 but leave the atmosphere faster. Reducing emissions of CH4 and N2O will decrease concentrations in the atmosphere more quickly.Greenhouse gases (GHGs) absorb heat from Earth’s surface, warming the atmosphere and changing our climate. New Zealand’s share of GHG emissions is very small, but our gross emissions per person are high. Emissions mainly come from combustion of fossil fuels that emit carbon dioxide (CO2), and agriculture which emits methane (CH4) and nitrous oxide (N2O). Carbon dioxide remains in the atmosphere much longer than other major GHGs. Because of this, today’s global CO2 emissions will continue to influence atmospheric CO2 concentrations for a very long time. Methane and N2O trap heat better than CO2 but leave the atmosphere faster.
More information on this dataset and how it relates to our Environmental reporting indicators and topics can be found in the attached data quality pdf.

When nutrients accumulate in lakes (referred to as ‘nutrient enrichment’) above certain levels, they can make the lakes murky and green with algae, and lower oxygen levels. Lakes with extremely poor water quality are rarely suitable for recreation and provide poor habitats for aquatic species.

Trends in the following parameters are provided:
Trophic Level Index 3 (TLI)
Chlorophyll-a (CHLA)
Bottom-water dissolved oxygen (DObottom)
Ammoniacal nitrogen (NH4N)
Oxidised nitrogen (NO3N)
Total nitrogen (unfiltered) (TN)
Dissolved reactive phosphorus (DRP)
Total phosphorus (unfiltered) (TP)

For more information please see:
Larned, S, Snelder, T, Unwin, M, McBride, G, Verburg, P, McMillan, H (2015).Analysis of Water Quality in New Zealand lakes and Rivers: data sources, data sets, assumptions, limitations, methods and results. NIWA Client Report no. CHC2015-033. Available at data.mfe.govt.nz/x/DDui3u from the Ministry for the Environment dataservice.

This dataset relates to the "Lake water quality: Trophic Level Index" measure on the Environmental Indicators, Te taiao Aotearoa website.

Influenza is a potentially life-threatening virus that spreads quickly from person to person. It is a significant public health issue in this country, with 10–20 percent of New Zealanders infected every year. While influenza outbreaks can occur all year round, rates peak in winter and spring. This is because the virus can survive longer outside the body in periods of colder weather and low absolute humidity (dry conditions).
This dataset relates to the "Influenza" measure on the Environmental Indicators, Te taiao Aotearoa website.

Extreme wave indexes estimate the occurrence of extreme wave events in coastal and oceanic waters. Extreme wave indexes estimate the number of times a significant wave height exceeds one of three threshold values for at least 12 hours in 24 marine regions. The three wave-height thresholds are four metres, six metres, and eight metres.
This indicator estimates the exceedances of wave-height thresholds for each year from 2008 to 2015 in coastal areas.
Significant wave height is a measure of the ‘typical’ wave height in a place over a time period. It is four times the standard deviation of the water surface if, for example, you were to measure water moving up and down a jetty piling for an hour. The largest individual wave will typically have a height around twice the significant wave height.
We use three wave-height thresholds because of the regional variation in extreme wave events. In general, the north experiences less exposure to consistently strong winds, and the waves generated by them, than the south. Four-metre tall waves are considered extreme in the northern-most parts of New Zealand but are more common in the south. For the southern-most parts of New Zealand, eight-metre waves better represent extreme wave events.

Greenhouse gases (GHGS) in the atmosphere absorb heat radiating from Earth, warming the atmosphere. Emissions from human activities increase the concentrations of these gases. Increases in these gases increase ocean acidity and are extremely likely to contribute to increased global temperatures, sea levels, and glacier melt. Monitoring GHG concentrations allows us to infer long-term impacts on ocean acidity, temperature, sea level, and glaciers.
Greenhouse gases are generally well mixed around the globe. We use ‘clean air’ observations from Baring Head, near Wellington, to estimate global concentrations of the greenhouse gases – carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and carbon monoxide (CO). These observations are made only when the air’s trajectory is from the south and away from any likely local sources of gas emissions. This gives an estimate representative of the concentrations over the Southern Ocean.
The observations tell us how the global atmosphere responds to increasing emissions of greenhouse gases, and are an internationally representative measure of global concentrations. However, the Southern Hemisphere has slightly less greenhouse gas concentrations than the Northern Hemisphere, as well as a smaller seasonal variation.
Further information can be found in:
Mikaloff Fletcher, SE, & Nichol, S (2014) Measurements of Trace Gases in Well-mixed Air at Baring Head: Trends in carbon dioxide, methane, nitrous oxide and carbon monoxide. Prepared for Ministry for the Environment. Available at data.mfe.govt.nz/x/cZzREp on the Ministry for the Environment dataservice (data.mfe.govt.nz/).
This dataset relates to the "Greenhouse gas concentrations" measure on the Environmental Indicators, Te taiao Aotearoa website.

The ocean waters surrounding New Zealand vary in temperature from north to south. They interact with heat and moisture in the atmosphere and affect our weather. Sea surface temperature changes with climate drivers such as El Niño, and will change with climate change. The sea surface temperature anomaly provides an indication of the heat change in the ocean.
Long-term changes and short-term variability in sea-surface temperatures can affect marine processes, habitats, and species. some species may find it hard to survive in changing environmental conditions.
The oceanic sea surface temperature data comes from the NIWA Sea surface temperature Archive (NSA). There are 2 datasets, of NSA Annual means and NSA Annual Anomolies, covering the Tasman, subtropical (STW) and Southern Antarctic (SAW) area and the total area. The data is available from 1993 to 2013 and the unit of measure is degrees celcius.
For further information please see:
Uddstrom, MJ (2015) Sea Surface Temperature Data and Analysis for the 2015 Synthesis Report. For Ministry for the Environment. Available at data.mfe.govt.nz/x/hRbGUJ on the Ministry for the Environment dataservice (data.mfe.govt.nz).
This dataset relates to the "Sea surface temperature" measure on the Environmental Indicators, Te taiao Aotearoa website.

Seabed trawling and dredging (where fishing gear is towed near or along the ocean floor) can physically damage seabed (benthic) habitats and species. These fishing methods can also stir up sediment from the seabed, creating sediment plumes that can smother sensitive species. Recovery times for affected habitats and species depend on their sensitivity and the area affected by trawling or dredging. Bottom trawling is carried out on or near the seabed in both shallow and deep waters. Dredging is carried out on the seabed in shallow waters and targets marine creatures such as scallops. This measure focuses on deepwater areas (waters deeper than 200m).