By Nguyen Cong Vinh

Introduction
The Food and Agriculture Organization (FAO) defines food security as a "situation that exists when all people, at all times, have physical, social, and economic access to sufficient, safe, and nutritious food that meets their dietary needs and food preferences for an active and healthy life". Viet Nam in Southeast Asia is an agricultural country with more than 86 million people (2008), living in an area of 32.924 million ha. Agricultural production plays an important role in national economic development and food security and contributes 20.3 per cent to the national economy. Changing policies and the land law after 1980 contributed to these gains. From the self consumption and self-supply economic system, since 1980, Vietnamese Government implemented new policies and strategies to develop national economic. This 'new re-thinking' policy was issued to move from 'the self consumption and self supply economy' into 'marketing economic rule'. Food production was prioritized with rice land increasing from 7.3 million ha in 1995 to 8.4 million ha in 2008.

Viet Nam imported rice in the early 1980s but become the second largest rice exporting country, after Thailand. Food production progressed greatly with production of 6.1 million tons in 1955, increasing to 14.4 million tons in 1980 and 43.3 million tons in 2008. However, agriculture and food production in Viet Nam faces big problems due to climate change. Climate change is threatening human life. Climate change affects agriculture and food production in complex ways. It affects food production directly through changes in agro-ecological conditions and indirectly by affecting growth and distribution of incomes, and thus demand for agricultural produce. Ranked as one of the top 5 countries in the world impacted by climate change by UNDP, Viet Nam was chosen for this study on climate change and human development.

This article is to review the current food production and challenges under climate change in Viet Nam.

Population as a pressure for food production
Viet Nam is a narrow land with high population density. The population has been increasing from 72 million people in 1995 to 83.1 million in 2005 and 86.2 million people in 2008 (Statistic year book, 2008). Viet Nam has a high population density of 260 people/km2. The Red river delta has the highest density compared with other regions in the country, approximately 20 million people with a density of 933 people/km2. Population in rural areas consists of more than 72 per cent of total population throughout all regions, except the southeast region where the agricultural population consists of 42 per cent of total population. The southeast region has the second highest density with 543 people/km2, after Red river delta. This region includes Binh Duong, Dong Nai, Ba Ria - Vung Tau provinces and Ho Chi Minh City which have changed from agricultural provinces to industrial provinces.

The mountainous areas have less people than in the delta regions. Lowest density is in the western highlands (Dak Lack, Gia Lai, Kon Tum, Dak Nong and Lam Dong provinces) with a density of 92 people/km2.

Increasing population demands more food supply. By forecasting in the few next decades, the population of Viet Nam will increase annually with a rate of 1-1.2 per cent, reaching 100 million in 2020 and 120 million people in 2030. Average grain food production is projected to be 470 kg/capita/year in 2010 and 390 kg in 2020. The total food requirement will reach 47 million tons in 2010; 50.3 million tons in 2015; 53.2 million tons in 2020; and 58.3 million tons in 2030. Of this, rice required will be 31.1 million tons; 32.1 million tons; 35.2 million tons and 37.3 million tons, respectively (Vu Nang Dung, Hoang Tuan Hiep, 2009)

Agricultural and food production
Food production
The total area of Viet Nam is 32,924.1 km2 of which 9.4 billion ha (28.43 per cent) is agricultural land. In agricultural lands, the annual crops consist of 19 per cent, three times larger than the perennial crops. The annual crops include rice, maize, sweet potato, peanut, soybean and vegetables cultivated on flat lands in the delta. On upland soils, annual crops include maize, cassava and some vegetables. Largest agricultural land is distributed in Cuu Long river delta followed by the northern and southern central coasts and middle and northern mountain deltas and finally the western highlands. The most rice cultivation, in both area and production, is in Cuu Long river delta and the second in Red river delta.

Land for agricultural production has been increasing over time. Table 1 shows that land use increased in the agricultural sector over the last 53 years. Total cultivated lands were 4.7 million ha in 1955, increased to 7.1 million ha in 1990, 84 million ha in 2005 and 8.5 million ha in 2008. Food production is increasing from 4.7 million ha in 1955 to 7.1 million ha in 1990 and 7.4 million ha in 2008. The total food production is 6.1 million tons in 1955; 21.5 million tons in 1990 and 39.6 million tons in 2008. The average food production was 430.3 kg/capita/year during 1996-2002, increasing to 540.5 kg/capita/year (by 1.95 per cent) during 2002-2006, and 503 kg/capita in 2008.

During 1976-1986, food production increased annually by 3 per cent, with 18.4 million tons in 1986, but 1987 it went down to 17.6 million tons. Average food production reduced from 301 kg/capita to 282 kg/capita. Due to better weather conditions and changing management policies, agricultural production progressed better. Food income was obtained by trade of 19.6 million tons in 1988 and 21.4 million tons in 1989. In GDP, agricultural products contributed 50 per cent (1988), 2 times higher than from industrial products, while population pressure is increasing resulting in a decrease of cultivated land/capita. It was 0.19 ha/capita in 1955, down to an average of 0.12 ha/capita during the '80s, and 0.10 ha/capita in 2008 (Table 1).

By forecasting over the next few decades, the population of Viet Nam will increase at an average annual rate of 1-1.2 per cent, reaching 100 million people by 2020 and 120 million people in 2030. Grain food requirement is estimated at 470 kg/capita/year by 2010 and 390 kg by 2020. National reserves are at 1.3 million tons/year from now through 2010, 1.5 million tons from 2010-2015, and 2-2.5 million tons in 2020. This means the food requirement of Viet Nam is estimated at 47 million tons in 2010, 50.3 million tons in 2015, 53.2 million tons in 2020 and 58.3 million tons in 2030. The main cereal crops are rice (62-66 per cent) and maize (13-17 per cent) (Vu Nang Dung, Hoang Tuan Hiep, 2009).

Rice production
Rice cultivation is a long standing and traditional product of Viet Nam playing the most important role in food production, agricultural and economical development. Rice areas are distributed throughout the whole country. Rice production contributed about 37 per cent of total agricultural income and 26 per cent of exported agricultural products during the period 2000-2004.

In the northern part, rice is mainly cultivated in two crops per year (spring rice and summer rice). In central and southern parts, rice can be grown one more season (three crops per year). Red river delta and Cuu Long river delta are the main rice regions, where rice covers 2/3 of cultivated areas and produce about 70 per cent of total rice production in the country.

Figure 1. Rice production (a) and Maize production (b) in Viet Nam

In the Red river delta, rice is dominantly planted on the fluvial and alluvial soils. Rice -based cropping systems are rice-rice, rice-corn, rice-rice potato/sweet potato, rice-rice corn/bean, rice-rice-vegetables (tomato, cabbage). In Cuu Long river delta, rice-based cropping systems are rice-rice, rice-rice-rice. In addition, rice is also cultivated in a mixed farming system such as rice-fish or rice-shrimp.

Due to application of new technology in rice production such as new varieties, better soil management and important policies to develop agriculture (land use rights to farmers/households and reduced land tax for farmers), rice production in Viet Nam has been increasing yearly in both area and productivity. During the period 1990-1999, rice area was increased from 6 million ha to 7.66 million ha; production was increased by 7.2 per cent/year. During the period 2000-2007, rice area reduced frequently to 6.7 million ha from 7.4 million ha. However, rice production increased from 32.5 million tons (2000) to 35.9 million tons (2007).

In 2008, rice area increased to 7.4 million ha and production increased to 38.6 million tons (General statistic year book 2008). In 1989, for the first time Viet Nam exported rice totalling 1.4 million tons with an export value of US$310 million. Afterward, food production has continuously increased. Exported rice amounted to 5.3 million tons in 2005 with an export return of US$1.4 billion (N.D. Bich, http://vietbao.vn/Kinh-te/Xuat-khau-gao-Tra-gia-cho-su-qua-da/ 30156413/87/).

Maize production
Maize is the second most important food crop in Viet Nam, next to rice. It is the substitute staple in periods of rice shortage, especially for people in the rural areas and mountainous regions. Maize is also the primary source of feed for Viet Nam's poultry and livestock industry and is, therefore, an important source of income for many farmers. Maize production has risen sharply since 1990, when only 431,800 ha were planted to maize, yielding an average of 1.6 t/ha for a total production of 671,000 tons. Since then, the government has strongly supported maize hybrid technology and the resultant hybrid maize varieties have been widely adopted by farmers. In addition, the livestock and poultry industry have grown, creating a need for more maize to use as feed. From 1990 to 1999, total maize production increased by 161 per cent. The total area planted to maize by 1990 was 6.47 million ha yielding an average of 1.5 t/ha; and 8.35 million ha and 2.53 t/ha in 1999. Then, a significant increase was obtained in 2008 where the total maize area planted reached 1.13 million ha with an average yield of 4t/ha from a total production of 4.35 million tons in whole country (Viet Nam Statistical Yearbook, 2009). This dramatic change made a positive economic contribution to many rural areas of Viet Nam.

Rapid economic growth and accelerated urbanization in the country are expected to create an even higher demand for maize. This trend will lead to an intensification of current maize production systems, with more land being devoted to maize cultivation, particularly in the marginal uplands. However, the increasing commercialization and intensification of maize production in these upland areas could have negative environmental consequences. Viet Nam's challenge is to provide more maize for an expanding market, while preserving the natural resource base and the environment through careful agricultural planning. Effective policy design and implementation must be based on comprehensive and accurate data on the current state of upland maize-based farming systems.

National poverty and reduction
Even though Viet Nam is a food export country, Vietnamese Government and Vietnamese Communist Party always set food security as a priority in making policies during the process of economic development. The Tenth Congress of Vietnamese Communist Party agreed that Viet Nam must plan the area for growing rice in order to get stable rice production and obtain food security. The policies supporting food security include policies related to rice growing such as land policy, investments and trade policy. In terms of land policy, in 1993 the land law was issued allowing rice farmers to have more autonomy in making production decisions. However, in order to obtain food security, the Government issued Decisive No. 68/2001/ND-CP on 01 October 2001 that attempted to control paddy land by limiting farmers to convert their paddy land to other crops or other uses. In 2006, Vietnamese Assembly issued Decisive No. 57/2006/NQ-QH11 that strictly controls converting paddy land into other uses. Moreover, farmers are also exempted from agricultural land tax. On 18 April 2008, the Prime Minister signed Decisive 391/2008/Q�-TTg to check the implementation of agricultural land use plan, and rice land in particular. The Vietnamese Government has also supported food security by providing public investments in agriculture, especially in building irrigation systems for areas growing rice. About 80 per cent of irrigation investments was allocated to rice production. Moreover, on 22 October 2004, the Prime Minister signed the Decisive No. 184/2004/Q�-TTg, to improve the irrigation systems connecting farmer land and the rural transportation system (Nguyen Van Ngai, n.d.)

Table 2. Rural poverty situation in Viet Nam (1999)

Source: Computed using poverty data for 1999 in Population and Socio
economic Statistics Data 1975-2001, General Statistics Office, 2002.

Agriculture is the most important source of income in the country, although the contribution of rice and maize to farm income varied widely among agro-ecologies, ranging from 0.5 per cent to 32.7 per cent of the total farm income, and making up less than 40 per cent of total farm income. The sale of maize made a higher contribution to farm income in the upland agro-ecologies compared to that of the lowland agro-ecologies. Upland maize farmers, however, have less non-farm income than farmers in the lowlands. Approximately 16 per cent of the country's total population is very poor, with the highest levels of poverty (19.7-23.3 per cent) recorded in 1999 in the northern upland and in the upland and lowland areas of the central highlands central coast (Table 2).

However, poverty remains a problem that needs to be addressed in the future. The poverty rate in country has been reduced from 18.1 per cent in 2004 to 15.5 per cent in 2006 and 14.8 per cent in 2007. In the mountainous areas, poverty remains high at 38.1 per cent in northern west region and 25.8 per cent in northern central coast by 2007 (Statistic year book 2007).

Food crop production as affected by climate change
Agro-forestry and aquaculture production have been facing difficulties because of the greenhouse gas effect of raising air temperatures, thawing ice, rising sea water levels, harmful rains, windstorms and floods. Generally, climate change is very complex but the trend is longer, more serious changes such as increasing air temperatures, very damaging cold temperatures and floods (INFOTERRA VN, Xl, Ministry of Agriculture and Rural Development, 27/5/2008).

FAO stated that in 2008 climate change has contributed to increasing the number of those experiencing hunger, a total which now is estimated at 1 billion, 100 million higher than in 2007 due to the world financial crisis (To Van Tuong, 2009, http://www.vncold.vn/Web/Content.aspx? distid=1915).

Additionally, hundreds of thousands of hectares of land are being seriously degraded. Partial desertification in Viet Nam occurred on 7.85 million ha, distributed on the western highland plateau, western north and Long Xuyen quadrangular (Quang Thuan, 2004). Economic loss was estimated at US$ 125 billion per year (Khong Loan, http://www.tuoitre.com.vn/Tianyon/ PrintView.aspx? ArticleID= 319151& Channel D=2).

Flooding usually happens from May-June and September-October in the Northern part, and from June-July to October-November in Northern central part, October-December in Southern central part, June-December in Western highlands and July-December in Southern part.

In the Red river delta, two extremely strong floods happened in August 1945 and August 1971. They damaged many dams and dykes in many provinces. There was additional flooding in the years 1913, 1915, 1917, 1926, 1964, 1968, 1969, 1970, 1986, 1996 and 2002.

In the central area, large-scale flooding happened in the years 1964, 1980, 1983, 1990, 1996, 1998, 1999, 2001and 2003 and in Cuu Long river delta, harmful flooding occurred in the years 1961, 1966, 1978, 1984, 1991, 1994, 1996, 2000 and 2001.

Over the last 100 years, it is estimated that there were 493 typhoons and low tropical pressures in Viet Nam, which is an average of 4-5 times per year. In the last three decades, the number of typhoons was 55 in 1960-1969; 66 in 1970-1979 and 72 in 1980-1989. More recent typhoons occur with higher frequency and are more harmful.

Natural calamities cause serious losses every year. Crops were damaged throughout the country. As an example, 700,000 ha of rice land was damaged as well as 154,000 ha of lowland rainfed crops in Thanh Hoa; 4,500 thousand ha of rice and 210 thousand ha of lowland rainfed crops in Nghe An; and 37 thousand and 210 thousand ha, respectively in Ha Tinh province.

Dry and hot weathers cause soil degradation and desertification. The desertification occurred on 700 thousand ha of which most were on sandy soils. Salinity and sulfate acidity occurs on 30,000 ha in Cuu Long river delta. The value of cultivated area with complete loss was more than 8,000 billion VN dong in 1996, 7,800 billion VN dong in 1997 and 3,500 billion VN dong in 2008. Flooded and lost areas of aquaculture were estimated at 100,000-135,000 ha (http://www.hymetdata.gov.vn).

Summary
Viet Nam is an agricultural country with narrow land and dense population. Agricultural production is being developed and achieved great progress in recent years contributing about 20-40 per cent to GDP. Food production is a priority so that cultivated rice lands increased from 7.3 million ha in 1995 to 8.5 million ha in 2008. Food production has increased from 6.1 million tons in 1955 to 43.0 million tons in 2008, an average of 224 and 503 kg/capita/year, respectively.