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ONLANGS WAARNEEMDE VERANDERINGE. L. DE WET. INLEIDING. Indien ons onsself afvra : IS daar enige onlangse waarneemde veranderinge , wat sal ons antwoord wees ? En dan , WATTER veranderinge ? Is dit veranderinge in die klimaat ? vegetasie ? Seevlaktoename ?
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ONLANGS WAARNEEMDE VERANDERINGE L. DE WET
INLEIDING • Indienonsonsselfafvra: IS daarenigeonlangsewaarneemdeveranderinge, watsalonsantwoordwees? • En dan, WATTER veranderinge? • Is ditveranderinge in • die klimaat? • vegetasie? • Seevlaktoename? • temperatuur en reenval? Watpresiesmoetonsuitvind? • Indienons ‘n raaiskootmoetneem (niebaiewetenskapliknie) souonssêdaar is veranderingewatonskansien (of voelwat) alreedsplaasgevnd het, bv, toename in vloede, vure, vegetasiebedekking, afstandevanaf die see, ens. • Is daar ‘n toename of is ditmaar ‘n toename in tegnologie? • Is daarveranderinge in the gemiddelde temperature en presipitasie? • Is die veranderingea.g.v. veranderinge in natuurlikeveranderlikheid of a.g.v. klimaatsverandering? • Waar pas uiterstes in ? • Die internet het baieinligting – maarwatkanonsglo en watnie?
INLEIDING • Figuur 1 Skematiesevoorstelling van die twee hoofdenkendeskolet.o.v. klimaatsverandering
INLEIDING • Daar is baieonderwerpeom van tekiessoos: • See-vlaktoename • Vegetasiebedekking • Siektes • Ekosisteme, ens.
Figure 1 shows the evolution of global mean sea level in the past and as projected for the 21st century for the SRES A1B scenario. • FAQ 5.1, Figure 1. Time series of global mean sea level (deviation from the 1980-1999 mean) in the past and as projected for the future. For the period before 1870, global measurements of sea level are not available. The grey shading shows the uncertainty in the estimated long-term rate of sea level change (Section 6.4.3). The red line is a reconstruction of global mean sea level from tide gauges (Section 5.5.2.1), and the red shading denotes the range of variations from a smooth curve. The green line shows global mean sea level observed from satellite altimetry. The blue shading represents the range of model projections for the SRES A1B scenario for the 21st century, relative to the 1980 to 1999 mean, and has been calculated independently from the observations. Beyond 2100, the projections are increasingly dependent on the emissions scenario (see Chapter 10 for a discussion of sea level rise projections for other scenarios considered in this report). Over many centuries or millennia, sea level could rise by several metres (Section 10.7.4).
Sea level rise – Update • 2012 update on sea-level rise • http://www.bbc.co.uk/news/science-environment-19702450
http://www.skepticalscience.com/news.php?p=2&t=51&&n=349 Friday, 3 September, 2010 Hurricanes And Climate Change: Boy Is This Science Not Settled! • The current research into the effects of climate change on tropical storms demonstrates not only the virtues and transparency of the scientific method at work, but rebuts the frequent suggestion that scientists fit their findings to a pre-determined agenda in support of climate change. In the case of storm frequency, there is no consensus and reputable scientists have two diametrically opposed theories about increasing frequencies of such events. • The background to these enquiries stems from a simple observation: extra heat in the air or the oceans is a form of energy, and storms are driven by such energy. What we do not know is whether 1) we might see more storms as a result of extra energy or, as other researchers believe, 2) the storms may grow more intense, but the number might actually diminish. • What do the records show? According to the Pew Centre, “Globally, there is an average of about 90 tropical storms a year”. The IPCC AR4 report (2007) says regarding global tropical storms: "There is no clear trend in the annual numbers [i.e. frequency] of tropical cyclones."
But this graph, also from the Pew Centre, shows a 40% increase in North Atlantic tropical storms over the historic maximum of the mid-1950, which at the time was considered extreme: • But while the numbers are not contested, their significance most certainly is. Another study considered how this information was being collected, and research suggested that the increase in reported storms was due to improved monitoring rather than more storms actually taking place. • And to cap it off, two recent peer-reviewed studies completely contradict each other. One paper predicts considerably more storms due to global warming. Another paper suggests the exact opposite – that there will be fewer storms in the future. • What can we conclude from these studies? About hurricane frequency – not much; the jury is out, as they say. About climate change, we can say that these differing approaches are the very stuff of good science, and the science clearly isn’t settled! It is also obvious that researchers are not shying away from refuting associations with climate change, so we can assume they don’t think their funding or salaries are jeopardised by research they believe fails to support the case for AGW. The scientific method is alive and well.
Table 1: Comparison of the TREES map (true kt, 1992) and the updated land cover map (estimatedke, 1998). All values in % of the total nr. of pixels (4,136,571). 88.9% of the pixels are correctlyclassified or unchanged (ke=kt), 11.1% are misclassified or changed (ke≠ kt)
The 2007 Arctic sea ice minimum, on September 16, 2007, reached the lowest ice extent in the satellite record.—Credit: National Snow and Ice Data Center
Arctic sea ice extent for March, 2009, was 15.16 million square kilometers (5.85 million square miles). The magenta line shows the 1979 to 2000 median extent for that month. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data. —Credit: National Snow and Ice Data Center
http://ocean.dmi.dk/arctic/plots/icecover/icecover_2010.png Sea ice extent for the past 5 years (in million km2) for the northern hemisphere, as a function of date.
SONVLEKAKTIWITEIT • Hoof verwysing: Alexander, W.R.J., 2008. The likelihood of a Global drought 2009-2016. • Die aarde se klimaat word deur die son gedryf. • Veranderinge in klimaatbehoortdustoegeskryfte word aanveranderinge in sonaktiwiteit. • Die IPCC gebruikGlobaleoppervlaktemperatuur data vanaf 1850 omklimaatsveranderingtebevestig.
SONVLEKAKTIWITEIT • Alexander het hierdiedatastel + sonvlekdatabekom en die temperatuurveranderingsoos in Figuur 1 geplot.
SONVLEKAKTIWITEIT • By so ‘n analise is ditalgemeenkorrekom die datarekord in twee te Verdeel – die jaar1913 is dus gepasomdatdit die begin is van die DubbeleSonvleksiklus. Resultate het die volgende opgelewer: 1913-2006: Toenemendesonvlekaantal en Ta. 1850-1912: Afname in sonvlekaantal en Ta.
SONVLEKAKTIWITEIT • Figuur 1 is korrekmaaris gebruikdeur IPCC omantropogenieseglobaleverwarminggekoppel met toename in KHG testeun. • VolgensFiguur 1 wys die inteendeel: daar is geenvolhoubaretoename in Ta sedert 1998. • IPCC het nie die volgendestapgeneem en probeerom die son se invloed (natuurlikeveranderlikheid) teeliminieernie – hulle le die blaam op die gansewereld se bevolking. • ‘n Eenvoudige Excel analise is gedoenomsonaktiwiteit en Ta met mekaartekoppel.
SONVLEKAKTIWITEIT • Hierdieanalisebewysdaar is ‘n sikliesekorrelasietussen Ta en sonvlekaktiwiteit. • Dit is ookwelbekend in S.A. (100 jaar al) datdaar ‘n sinkroniesekorrelasie is tussensonaktiwiteit, reenval en riviervloei. • Wisselendesonvleksiklussehouookverband met versnelling en verlangsaming van die son soosditdeur die ruimtebeweeg. • Resultate van jaarliksetydskaleverander van resultatewaarinsinkroniesesonvleksilussegebruik is.
SONVLEKAKTIWITEIT • Die vraag is: Wattertydkskaalmoetgebruik word? • Antwoord: dubbelesonvlekskiluslengte (21 jaar). • Tabel 1: 1843 – 1866 (24 j) • 1867 – 1888 (22 j), etc. • Die sonvlek minimums wat met dubbelesonvleksiklusverbandhou is dan in 1843, 1866, ens.
SONVLEKAKTIWITEIT • Tabel 3 wysperiodes of jaregekoppel to nat- en droeperiodes (NIE jaarliksgekoppel met klimaatnie) • Hierdietipe van analise (volgens Alexander, 2008) is baie NB en verander die resultate van analisesdeurwetenskaplikes. • Om Tabel 4 op te trek is dusmaklikindien die metode van Alexander gevolg word.
SONVLEKAKTIWITEIT • Tabel 4: linkerkantsekolum – jarewaarindubbelesonvlekaktiwiteit begin. • Boonstery: periodejaarsyfers. • Groepering van nat- en droereekse en die korrelasie met dubbelesonvlekaktiwiteit is baieduidelik. • Vergelyk met Figuur 2: Dominansie van natjarewatverbandhou met eerstesonvleksiklus (jare 1-11) en • Droejarewatverbandhou met die tweedesonvleksiklus (jare 12-22).
SONVLEKAKTIWITEIT • Hierdietipesikluskangebruik word om die volgendesiklustevoorspel. • NB – die periodisiteit (en nie die sonvleksiklus as sulks) word as die voorspellingsgereedskpgebruik. • Figuur 3 – riviervloeivoorspellingsmodel. • Gemiddeldeafloophoeveelhede is berekenvolgens die metodebeskryf en geplotvanaf 1995. • Let op die bogemiddelderiviervloeivir die jaar 13 (2008) en
SONVLEKAKTIWITEIT • die ondergemiddelderiviervloeivanaf die periode 14 vorentoe. • Hierdievoorspellingsmodel is getoets en geverifieer. • Ditbetekendatdaar ‘n periode van droogtesalvoortduurvanaf 2009 en vorentoe. • [Onthou die voorkoms van hoe reenval in 2009 kan as ‘n uiterstebeskou word en as sulks nog steeds deel van ‘n droogte scenario.] • Die sonvlek minimum het in Jan 2008 voorgekom. Ditbetekendatdaar min sonvlekadktiwiteitplaasvind en kan tot globaleverkoeling lei.
