Knowledge

Doubling time

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2890: 1618: 2838: 2850: 112:. Clay tablets from circa 2000 BCE include the exercise "Given an interest rate of 1/60 per month (no compounding), come the doubling time." This yields an annual interest rate of 12/60 = 20%, and hence a doubling time of 100% growth/20% growth per year = 5 years. Further, repaying double the initial amount of a loan, after a fixed time, was common commercial practice of the period: a common 2902: 2862: 1617: 1416:
When applied to the constant growth in consumption of a resource, the total amount consumed in one doubling period equals the total amount consumed in all previous periods. This enabled U.S. President Jimmy Carter to note in a speech in 1977 that in each of the previous two decades the world had used
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As an example, Canada's net population growth was 2.7 percent in the year 2022, dividing 72 by 2.7 gives an approximate doubling time of about 27 years. Thus if that growth rate were to remain constant, Canada's population would double from its 2023 figure of about 39 million to about 78 million by
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loan of 1900 BCE consisted of loaning 2 minas of gold, getting back 4 in five years, and an Egyptian proverb of the time was "If wealth is placed where it bears interest, it comes back to you redoubled."
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For example, with an annual growth rate of 4.8% the doubling time is 14.78 years, and a doubling time of 10 years corresponds to a growth rate between 7% and 7.5% (actually about 7.18%).
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more oil than in all of previous history (The roughly exponential growth in world oil consumption between 1950 and 1970 had a doubling period of under a decade).
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Examining the doubling time can give a more intuitive sense of the long-term impact of growth than simply viewing the percentage growth rate.
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by the exponent of growth, or approximated by dividing 70 by the percentage growth rate (more roughly but roundly, dividing 72; see the
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Graphs comparing doubling times and half lives of exponential growths (bold lines) and decay (faint lines), and their 70/
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Cell doubling time can be calculated in the following way using growth rate (amount of doubling in one unit of time)
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and has a constant doubling time or period, which can be calculated directly from the growth rate.
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is the time it takes for a population to double in size/value. It is applied to
2746: 2601: 2045: 1448:, and assuming a constant growth rate, the doubling time can be calculated as 78: 74: 2075:, 2008, page 33 (box "Hint on reinforcing feedback loops and doubling time"). 2411: 2298: 2185: 2035: 2017: 1605: 1592: 93: 39: 1951:{\displaystyle {\text{doubling time}}={\frac {\ln(2)}{\text{growth rate}}}} 2901: 251:
Some doubling times calculated with this formula are shown in this table.
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http://geography.about.com/od/populationgeography/a/populationgrow.htm
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for a material undergoing a constant negative relative growth rate or
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The following is the known doubling time for the following cells:
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Why the “Miracle of Compound Interest” leads to Financial Crises
350:= doubling period (time it takes for object to double in number) 2233: 58:, and many other things that tend to grow over time. When the 1784:{\displaystyle r={\frac {\ln \left(N(t)/N_{0}\right)}{t}}} 108:
The notion of doubling time dates to interest on loans in
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Miriam Lichtheim, Ancient Egyptian Literature, II:135.
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(August 2007). 69:This time can be calculated by dividing the 2379: 2252: 2238: 2230: 2193: 1924: 1916: 1914: 1887: 1865: 1842: 1836: 1802: 1764: 1755: 1729: 1721: 1691: 1681: 1660: 1548: 1538: 1532: 1503: 1491: 1478: 1462: 1456: 306: 297: 293: 283: 262: 228: 206: 171: 159: 153: 2099: 2097: 2095: 1963: 1308: 1206: 1104: 1002: 900: 798: 696: 594: 492: 390: 2885: 2057: 317:{\displaystyle N(t)=N_{0}2^{t/T_{d}}} 7: 2861: 136:, the formula for the doubling time 2803:Systems theory in political science 338:) = the number of objects at time 27:Time required to double a quantity 25: 2900: 2888: 2860: 2848: 2837: 2836: 1703:{\displaystyle N(t)=N_{0}e^{rt}} 1616: 1858:= the number of cells at time 0 1598:The equivalent concept in base- 2793:Systems theory in anthropology 1939: 1933: 1826:= the number of cells at time 1813: 1807: 1752: 1746: 1671: 1665: 1556: 1529: 1518: 1512: 1497: 1471: 273: 267: 254:Simple doubling time formula: 216: 197: 186: 180: 128:For a constant growth rate of 1: 2798:Systems theory in archaeology 2116:Have we caught your interest? 2069:Thinking in Systems: A Primer 359:= initial number of objects 79:derivations of this formula 2959: 2170:"Human cardiac stem cells" 1645:Cell culture doubling time 1583:The equivalent concept to 2832: 2430: 2382: 2294:Coupled human–environment 1995:29 Â± 10 hours 1902:= time (usually in hours) 2213:Doubling Time Calculator 2073:Chelsea Green Publishing 1989:Cardiac/heart stem cell 18:Population doubling time 2943:Mathematics in medicine 2627:Charles A. S. Hall 2186:10.1073/pnas.0706760104 1635:approximations. In the 84:The doubling time is a 2907:Business and economics 2547:Ludwig von Bertalanffy 1978:Mesenchymal Stem Cell 1952: 1896: 1874: 1852: 1820: 1785: 1704: 1569: 318: 242: 110:Babylonian mathematics 71:natural logarithm of 2 2928:Temporal exponentials 2824:Principia Cybernetica 2537:Anthony Stafford Beer 2407:Sociotechnical system 2008:Albert Allen Bartlett 1953: 1897: 1875: 1853: 1851:{\displaystyle N_{0}} 1821: 1786: 1705: 1570: 319: 243: 132: % within time 2687:Mihajlo D. Mesarovic 2662:Edward Norton Lorenz 2617:Jay Wright Forrester 2422:World-systems theory 2397:Earth system science 2041:Relative growth rate 1913: 1886: 1864: 1835: 1819:{\displaystyle N(t)} 1801: 1720: 1659: 1455: 261: 152: 145:  is given by 60:relative growth rate 2562:Kenneth E. Boulding 2180:(35): 14068–14073. 2138:"Life Technologies" 2106:, by Michael Hudson 386: 86:characteristic unit 44:resource extraction 2923:Population ecology 2692:James Grier Miller 2647:Faina M. Kirillova 2607:Heinz von Foerster 2597:Edsger W. Dijkstra 2557:Alexander Bogdanov 2542:Richard E. Bellman 2517:William Ross Ashby 2223:2006-08-28 at the 2031:Exponential growth 1948: 1892: 1870: 1848: 1816: 1781: 1700: 1565: 369: 314: 238: 64:exponential growth 2876: 2875: 2757:Manuela M. Veloso 2672:Humberto Maturana 2612:Stephanie Forrest 2582:C. West Churchman 2507:Russell L. Ackoff 2493: 2492: 2365:Positive feedback 2360:Negative feedback 2026:Exponential decay 1999: 1998: 1946: 1945: 1919: 1895:{\displaystyle t} 1873:{\displaystyle r} 1779: 1589:exponential decay 1560: 1554: 1411: 1410: 1407: 1406: 1305: 1304: 1203: 1202: 1101: 1100: 999: 998: 897: 896: 795: 794: 693: 692: 591: 590: 489: 488: 236: 220: 214: 90:exponential decay 56:malignant tumours 52:compound interest 36:population growth 16:(Redirected from 2950: 2905: 2904: 2893: 2892: 2884: 2864: 2863: 2852: 2840: 2839: 2752:Francisco Varela 2484:Systems thinking 2417:Urban metabolism 2380: 2254: 2247: 2240: 2231: 2200: 2199: 2197: 2165: 2159: 2158: 2156: 2155: 2149: 2143:. Archived from 2142: 2134: 2128: 2125: 2119: 2113: 2107: 2101: 2090: 2089: 2088:. 22 March 2023. 2082: 2076: 2062: 2013:Binary logarithm 1964: 1957: 1955: 1954: 1949: 1947: 1943: 1942: 1925: 1920: 1917: 1901: 1899: 1898: 1893: 1879: 1877: 1876: 1871: 1857: 1855: 1854: 1849: 1847: 1846: 1825: 1823: 1822: 1817: 1790: 1788: 1787: 1782: 1780: 1775: 1774: 1770: 1769: 1768: 1759: 1730: 1709: 1707: 1706: 1701: 1699: 1698: 1686: 1685: 1620: 1579:Related concepts 1574: 1572: 1571: 1566: 1561: 1559: 1555: 1553: 1552: 1543: 1542: 1533: 1521: 1504: 1496: 1495: 1483: 1482: 1467: 1466: 1309: 1207: 1105: 1003: 901: 799: 697: 595: 493: 391: 387: 368: 323: 321: 320: 315: 313: 312: 311: 310: 301: 288: 287: 247: 245: 244: 239: 237: 229: 221: 219: 215: 207: 189: 172: 164: 163: 77:for details and 54:, the volume of 21: 2958: 2957: 2953: 2952: 2951: 2949: 2948: 2947: 2933:Economic growth 2913: 2912: 2911: 2899: 2887: 2879: 2877: 2872: 2828: 2807: 2781: 2722:Anatol Rapoport 2707:Talcott Parsons 2682:Donella Meadows 2657:Allenna Leonard 2577:Mary Cartwright 2572:Kathleen Carley 2532:Gregory Bateson 2527:BĂ©la H. Bánáthy 2489: 2426: 2375: 2369: 2355:Limiting factor 2350:Leverage points 2333: 2271: 2263: 2261:Systems science 2258: 2225:Wayback Machine 2209: 2204: 2203: 2167: 2166: 2162: 2153: 2151: 2147: 2140: 2136: 2135: 2131: 2126: 2122: 2118:by John H. Webb 2114: 2110: 2102: 2093: 2084: 2083: 2079: 2065:Donella Meadows 2063: 2059: 2054: 2004: 1926: 1911: 1910: 1906:Doubling time: 1884: 1883: 1862: 1861: 1838: 1833: 1832: 1799: 1798: 1760: 1742: 1738: 1731: 1718: 1717: 1687: 1677: 1657: 1656: 1647: 1642: 1641: 1640: 1626: 1621: 1581: 1544: 1534: 1522: 1505: 1487: 1474: 1458: 1453: 1452: 1447: 1440: 1433: 1426: 1322: 1220: 1118: 1016: 914: 812: 710: 608: 506: 404: 380:given constant 379: 371:Doubling times 358: 348: 302: 289: 279: 259: 258: 190: 173: 155: 150: 149: 144: 123: 106: 28: 23: 22: 15: 12: 11: 5: 2956: 2954: 2946: 2945: 2940: 2935: 2930: 2925: 2915: 2914: 2910: 2909: 2897: 2874: 2873: 2871: 2870: 2858: 2846: 2833: 2830: 2829: 2827: 2826: 2821: 2815: 2813: 2809: 2808: 2806: 2805: 2800: 2795: 2789: 2787: 2783: 2782: 2780: 2779: 2777:Anthony Wilden 2774: 2772:Jennifer Wilby 2769: 2767:Norbert Wiener 2764: 2759: 2754: 2749: 2744: 2739: 2737:Claude Shannon 2734: 2729: 2724: 2719: 2714: 2712:Ilya Prigogine 2709: 2704: 2702:Howard T. Odum 2699: 2697:Radhika Nagpal 2694: 2689: 2684: 2679: 2674: 2669: 2667:Niklas Luhmann 2664: 2659: 2654: 2649: 2644: 2639: 2634: 2629: 2624: 2619: 2614: 2609: 2604: 2599: 2594: 2592:George Dantzig 2589: 2587:Manfred Clynes 2584: 2579: 2574: 2569: 2564: 2559: 2554: 2552:Margaret Boden 2549: 2544: 2539: 2534: 2529: 2524: 2519: 2514: 2512:Victor Aladjev 2509: 2503: 2501: 2495: 2494: 2491: 2490: 2488: 2487: 2477: 2472: 2467: 2462: 2457: 2452: 2447: 2442: 2437: 2431: 2428: 2427: 2425: 2424: 2419: 2414: 2409: 2404: 2402:Living systems 2399: 2394: 2389: 2387:Control theory 2383: 2377: 2371: 2370: 2368: 2367: 2362: 2357: 2352: 2347: 2341: 2339: 2335: 2334: 2332: 2331: 2326: 2321: 2316: 2311: 2306: 2301: 2296: 2291: 2286: 2281: 2275: 2273: 2265: 2264: 2259: 2257: 2256: 2249: 2242: 2234: 2228: 2227: 2215: 2208: 2207:External links 2205: 2202: 2201: 2160: 2129: 2120: 2108: 2091: 2077: 2056: 2055: 2053: 2050: 2049: 2048: 2043: 2038: 2033: 2028: 2023: 2015: 2010: 2003: 2000: 1997: 1996: 1993: 1990: 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Kay 2632:Mike Jackson 2567:Murray Bowen 2465:Pharmacology 2460:Neuroscience 2344: 2177: 2173: 2163: 2152:. 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Index

Population doubling time
population growth
inflation
resource extraction
consumption
compound interest
malignant tumours
relative growth rate
exponential growth
natural logarithm of 2
rule of 72
derivations of this formula
characteristic unit
exponential decay
half-life
Babylonian mathematics
Assyrian
exponential decay
half-life
e
e-folding


SVG version
Albert Allen Bartlett
Binary logarithm
e-folding
Exponential decay
Exponential growth
Half-life

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